### Start task command output example

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/migrate-sql-shards.md

Example JSON response from a successful start-task command showing task initialization status for multiple MySQL replica sources.

```json
{
   "result": true,
   "msg": "",
   "sources": [
       {
           "result": true,
           "msg": "",
           "source": "mysql-replica-01",
           "worker": "dm-192.168.11.111-9262"
       },

       {
           "result": true,
           "msg": "",
           "source": "mysql-replica-02",
           "worker": "dm-192.168.11.112-9262"
       }
   ],
   "checkResult": ""
}
```

--------------------------------

### DELETE statement setup and example

Source: https://github.com/pingcap/docs/blob/master/sql-statements/sql-statement-delete.md

Complete example showing table creation, data insertion, and deletion. Demonstrates the full workflow of creating a table, inserting rows, and deleting a specific row.

```sql
CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, c1 INT NOT NULL);
```

```sql
INSERT INTO t1 (c1) VALUES (1),(2),(3),(4),(5);
```

```sql
SELECT * FROM t1;
```

--------------------------------

### start-task command usage example

Source: https://github.com/pingcap/docs/blob/master/dm/dm-create-task.md

Start a data migration task by specifying a MySQL source and task configuration file.

```bash
start-task [ -s "mysql-replica-01"] ./task.yaml
```

--------------------------------

### Initialize Netlify Project for Continuous Deployment

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/integrate-tidbcloud-with-netlify.md

Start the automatic setup to connect your repository, creating a deploy key and webhook for continuous deployment.

```shell
netlify init
```

--------------------------------

### Create and activate a Python virtual environment

Source: https://github.com/pingcap/docs/blob/master/ai/integrations/vector-search-integrate-with-peewee.md

Navigates to the peewee quickstart example directory and creates and activates a Python virtual environment.

```bash
cd tidb-vector-python/examples/orm-peewee-quickstart
python3 -m venv .venv
source .venv/bin/activate
```

--------------------------------

### Example: Configure MySQL Client PATH in Git Bash (Windows)

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-proxysql-integration.md

An example demonstrating how to add a specific MySQL client bin directory to the PATH in Git Bash on Windows for a typical installation.

```bash
echo 'export PATH="/c/Program Files (x86)/mysql-8.0.31-winx64/bin":$PATH' >>~/.bash_profile
source ~/.bash_profile
```

--------------------------------

### Explain Query with Full Table Scan

Source: https://github.com/pingcap/docs/blob/master/system-variables.md

This example shows the query plan for a selection on a table, demonstrating a full table scan when `tidb_opt_prefer_range_scan` is not active or statistics are missing.

```sql
explain select * from t where age=5;
```

--------------------------------

### Create and Use a New Database

Source: https://github.com/pingcap/docs/blob/master/sql-statements/sql-statement-create-database.md

This example demonstrates how to create a new database, switch to it, create a table within it, and then list the tables to confirm creation.

```sql
mysql> CREATE DATABASE mynewdatabase;
Query OK, 0 rows affected (0.09 sec)

mysql> USE mynewdatabase;
Database changed
mysql> CREATE TABLE t1 (a int);
Query OK, 0 rows affected (0.11 sec)

mysql> SHOW TABLES;
+-------------------------+
| Tables_in_mynewdatabase |
+-------------------------+
| t1                      |
+-------------------------+
1 row in set (0.00 sec)
```

--------------------------------

### Clone PyMySQL sample application repository

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-sample-application-python-pymysql.md

Clone the TiDB Python PyMySQL quickstart sample repository to get started with the example application.

```shell
git clone https://github.com/tidb-samples/tidb-python-pymysql-quickstart.git
cd tidb-python-pymysql-quickstart
```

--------------------------------

### Demonstrate AUTO_INCREMENT with Offset and Increment in SQL

Source: https://github.com/pingcap/docs/blob/master/system-variables.md

This SQL example shows how to set `auto_increment_offset` and `auto_increment_increment` to customize the sequence of `AUTO_INCREMENT` values in a table.

```SQL
mysql> CREATE TABLE t1 (a int not null primary key auto_increment);
Query OK, 0 rows affected (0.10 sec)

mysql> set auto_increment_offset=1;
Query OK, 0 rows affected (0.00 sec)

mysql> set auto_increment_increment=3;
Query OK, 0 rows affected (0.00 sec)

mysql> INSERT INTO t1 VALUES (),(),(),();
Query OK, 4 rows affected (0.04 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> SELECT * FROM t1;
+----+
| a  |
+----+
|  1 |
|  4 |
|  7 |
| 10 |
+----+
4 rows in set (0.00 sec)
```

--------------------------------

### Clone the tidb-vector-python repository

Source: https://github.com/pingcap/docs/blob/master/ai/integrations/vector-search-integrate-with-django-orm.md

Clone the example repository to your local machine to get started with the tutorial.

```shell
git clone https://github.com/pingcap/tidb-vector-python.git
```

--------------------------------

### Setup Table, Insert Data, and Initial Query Plan

Source: https://github.com/pingcap/docs/blob/master/sql-statements/sql-statement-show-bindings.md

This snippet creates a table, populates it with sample data, analyzes the table statistics, and then shows the initial execution plan for a query before any SQL binding is applied.

```sql
mysql> CREATE TABLE t1 (
          id INT NOT NULL PRIMARY KEY auto_increment,
          b INT NOT NULL,
          pad VARBINARY(255),
          INDEX(b)
         );
Query OK, 0 rows affected (0.07 sec)

mysql> INSERT INTO t1 SELECT NULL, FLOOR(RAND()*1000), RANDOM_BYTES(255) FROM dual;
Query OK, 1 row affected (0.01 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> INSERT INTO t1 SELECT NULL, FLOOR(RAND()*1000), RANDOM_BYTES(255) FROM t1 a JOIN t1 b JOIN t1 c LIMIT 100000;
Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> INSERT INTO t1 SELECT NULL, FLOOR(RAND()*1000), RANDOM_BYTES(255) FROM t1 a JOIN t1 b JOIN t1 c LIMIT 100000;
Query OK, 8 rows affected (0.00 sec)
Records: 8  Duplicates: 0  Warnings: 0

mysql> INSERT INTO t1 SELECT NULL, FLOOR(RAND()*1000), RANDOM_BYTES(255) FROM t1 a JOIN t1 b JOIN t1 c LIMIT 100000;
Query OK, 1000 rows affected (0.04 sec)
Records: 1000  Duplicates: 0  Warnings: 0

mysql> INSERT INTO t1 SELECT NULL, FLOOR(RAND()*1000), RANDOM_BYTES(255) FROM t1 a JOIN t1 b JOIN t1 c LIMIT 100000;
Query OK, 100000 rows affected (1.74 sec)
Records: 100000  Duplicates: 0  Warnings: 0

mysql> INSERT INTO t1 SELECT NULL, FLOOR(RAND()*1000), RANDOM_BYTES(255) FROM t1 a JOIN t1 b JOIN t1 c LIMIT 100000;
Query OK, 100000 rows affected (2.15 sec)
Records: 100000  Duplicates: 0  Warnings: 0

mysql> INSERT INTO t1 SELECT NULL, FLOOR(RAND()*1000), RANDOM_BYTES(255) FROM t1 a JOIN t1 b JOIN t1 c LIMIT 100000;
Query OK, 100000 rows affected (2.64 sec)
Records: 100000  Duplicates: 0  Warnings: 0

mysql> SELECT SLEEP(1);
+----------+
| SLEEP(1) |
+----------+
|        0 |
+----------+
1 row in set (1.00 sec)

mysql> ANALYZE TABLE t1;
Query OK, 0 rows affected (1.33 sec)

mysql> EXPLAIN ANALYZE SELECT * FROM t1 WHERE b = 123;
+------------------------------- ---------+---------+-----------+----------------------+---------------------------------------------------------------------------+-----------------------------------+----------------+------+
| id                            | estRows | actRows | task      | access object        | execution info                                                            | operator info                     | memory         | disk |
+------------------------------- ---------+---------+-----------+----------------------+---------------------------------------------------------------------------+-----------------------------------+----------------+------+
| IndexLookUp_10                | 583.00  | 297     | root      |                      | time:10.545072ms, loops:2, rpc num: 1, rpc time:398.359µs, proc keys:297  |                                   | 109.1484375 KB | N/A  |
| ├─IndexRangeScan_8(Build)     | 583.00  | 297     | cop[tikv] | table:t1, index:b(b) | time:0s, loops:4                                                          | range:[123,123], keep order:false | N/A            | N/A  |
| └─TableRowIDScan_9(Probe)     | 583.00  | 297     | cop[tikv] | table:t1             | time:12ms, loops:4                                                        | keep order:false                  | N/A            | N/A  |
+------------------------------- ---------+---------+-----------+----------------------+---------------------------------------------------------------------------+-----------------------------------+----------------+------+
3 rows in set (0.02 sec)
```

--------------------------------

### Demonstrate `tidb_opt_ordering_index_selectivity_threshold` effect on index selection

Source: https://github.com/pingcap/docs/blob/master/system-variables.md

This example shows how setting `tidb_opt_ordering_index_selectivity_threshold` changes the optimizer's index selection for queries with `ORDER BY`, `LIMIT`, and filter conditions. The first `EXPLAIN` shows default behavior, and the second shows the effect after setting the threshold.

```sql
> EXPLAIN SELECT * FROM t WHERE b <= 9000 ORDER BY a LIMIT 1;
+-----------------------------------+---------+-----------+----------------------+--------------------+
| id                                | estRows | task      | access object        | operator info      |
+-----------------------------------+---------+-----------+----------------------+--------------------+
| Limit_12                          | 1.00    | root      |                      | offset:0, count:1  |
| └─Projection_25                   | 1.00    | root      |                      | test.t.a, test.t.b |
|   └─IndexLookUp_24                | 1.00    | root      |                      |                    |
|     ├─IndexFullScan_21(Build)     | 114.30  | cop[tikv] | table:t, index:ia(a) | keep order:true    |
|     └─Selection_23(Probe)         | 1.00    | cop[tikv] |                      | le(test.t.b, 9000) |
|       └─TableRowIDScan_22         | 114.30  | cop[tikv] | table:t              | keep order:false   |
+-----------------------------------+---------+-----------+----------------------+--------------------+

```

```sql
> SET SESSION tidb_opt_ordering_index_selectivity_threshold = 0.01;

```

```sql
> EXPLAIN SELECT * FROM t WHERE b <= 9000 ORDER BY a LIMIT 1;
+----------------------------------+---------+-----------+----------------------+-------------------------------------+
| id                               | estRows | task      | access object        | operator info                       |
+----------------------------------+---------+-----------+----------------------+-------------------------------------+
| TopN_9                           | 1.00    | root      |                      | test.t.a, offset:0, count:1         |
| └─IndexLookUp_20                 | 1.00    | root      |                      |                                     |
|   ├─IndexRangeScan_17(Build)     | 8748.62 | cop[tikv] | table:t, index:ib(b) | range:[-inf,9000], keep order:false |
|   └─TopN_19(Probe)               | 1.00    | cop[tikv] |                      | test.t.a, offset:0, count:1         |
|     └─TableRowIDScan_18          | 8748.62 | cop[tikv] | table:t              | keep order:false                    |
+----------------------------------+---------+-----------+----------------------+-------------------------------------+

```

--------------------------------

### Clone the sample application repository

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-sample-application-golang-sql-driver.md

Use these shell commands to clone the quickstart repository and navigate into its directory.

```shell
git clone https://github.com/tidb-samples/tidb-golang-sql-driver-quickstart.git
cd tidb-golang-sql-driver-quickstart
```

--------------------------------

### Clone peewee sample application repository

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-sample-application-python-peewee.md

Clone the TiDB Python peewee quickstart sample repository to get started with the sample application.

```shell
git clone https://github.com/tidb-samples/tidb-python-peewee-quickstart.git
cd tidb-python-peewee-quickstart
```

--------------------------------

### Demonstrating tidb_opt_distinct_agg_push_down in SQL

Source: https://github.com/pingcap/docs/blob/master/system-variables.md

This example illustrates how enabling the `tidb_opt_distinct_agg_push_down` variable changes the execution plan for `COUNT(DISTINCT)` queries, pushing the distinct aggregation to the Coprocessor.

```sql
mysql> desc select count(distinct a) from test.t;
+-------------------------+----------+-----------+---------------+------------------------------------------+
| id                      | estRows  | task      | access object | operator info                            |
+-------------------------+----------+-----------+---------------+------------------------------------------+
| StreamAgg_6             | 1.00     | root      |               | funcs:count(distinct test.t.a)->Column#4 |
| 	└─TableReader_10        | 10000.00 | root      |               | data:TableFullScan_9                     |
| 	  └─TableFullScan_9     | 10000.00 | cop[tikv] | table:t       | keep order:false, stats:pseudo           |
+-------------------------+----------+-----------+---------------+------------------------------------------+
3 rows in set (0.01 sec)

mysql> set session tidb_opt_distinct_agg_push_down = 1;
Query OK, 0 rows affected (0.00 sec)

mysql> desc select count(distinct a) from test.t;
+---------------------------+----------+-----------+---------------+------------------------------------------+
| id                        | estRows  | task      | access object | operator info                            |
+---------------------------+----------+-----------+---------------+------------------------------------------+
| HashAgg_8                 | 1.00     | root      |               | funcs:count(distinct test.t.a)->Column#3 |
| 	└─TableReader_9           | 1.00     | root      |               | data:HashAgg_5                           |
| 	  └─HashAgg_5             | 1.00     | cop[tikv] |               | group by:test.t.a,                       |
| 	    └─TableFullScan_7     | 10000.00 | cop[tikv] | table:t       | keep order:false, stats:pseudo           |
+---------------------------+----------+-----------+---------------+------------------------------------------+
4 rows in set (0.00 sec)
```

--------------------------------

### Clone TiDB AppFlow Integration Repository

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-aws-appflow-integration.md

Clone the integration example code repository from GitHub to get started with TiDB and Amazon AppFlow integration.

```bash
git clone https://github.com/pingcap-inc/tidb-appflow-integration
```

--------------------------------

### Prepare Sample Data with TiUP Demo

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-optimize-sql.md

Run this command to set up the `bookshop` sample data for performance tuning exercises. It populates the database with a specified number of books.

```shell
tiup demo bookshop prepare --host 127.0.0.1 --port 4000 --books 1000000
```

--------------------------------

### Kafka Broker Startup Script

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/setup-self-hosted-kafka-private-service-connect.md

Bash script to start a Kafka broker with Java environment setup. Sets JAVA_HOME to a bundled JDK installation within the script directory.

```shell
#!/bin/bash

# Get the directory of the current script
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# Set JAVA_HOME to the Java installation within the script directory
export JAVA_HOME="$SCRIPT_DIR/jdk-22.0.2"
```

--------------------------------

### Create Partitioned Table and Query PARTITIONS

Source: https://github.com/pingcap/docs/blob/master/information-schema/information-schema-partitions.md

This example demonstrates creating a hash-partitioned table and then querying the `PARTITIONS` table to retrieve its partition details.

```sql
CREATE TABLE test.t1 (id INT NOT NULL PRIMARY KEY) PARTITION BY HASH (id) PARTITIONS 2;
SELECT * FROM PARTITIONS WHERE table_schema='test' AND table_name='t1'\G
```

--------------------------------

### Start n8n with npm

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/integrate-tidbcloud-with-n8n.md

Install and start n8n using npx after installing Node.js on your workspace.

```shell
npx n8n
```

--------------------------------

### Example: List all available user profiles

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/ticloud-config-list.md

Demonstrates how to list all available user profiles without any additional flags.

```shell
ticloud config list
```

--------------------------------

### Safe start output example

Source: https://github.com/pingcap/docs/blob/master/production-deployment-using-tiup.md

Example output from a successful safe start operation showing the auto-generated root password that is displayed only once.

```shell
Started cluster `tidb-test` successfully.
The root password of TiDB database has been changed.
The new password is: 'y_+3Hwp=*AWz8971s6'.
Copy and record it to somewhere safe, it is only displayed once, and will not be stored.
The generated password can NOT be got again in future.
```

--------------------------------

### Convert Subquery to Join and Aggregation in SQL

Source: https://github.com/pingcap/docs/blob/master/system-variables.md

This variable enables an optimization rule that converts `IN` subqueries into join and aggregation operations for improved performance. The examples show the original subquery and its converted forms.

```SQL
select * from t where t.a in (select aa from t1);
```

```SQL
select t.* from t, (select aa from t1 group by aa) tmp_t where t.a = tmp_t.aa;
```

```SQL
select t.* from t, t1 where t.a=t1.aa;
```

--------------------------------

### Install and Enable NTP Service on CentOS 7

Source: https://github.com/pingcap/docs/blob/master/check-before-deployment.md

Run this command to manually install `ntp` and `ntpdate`, start the `ntpd` service, and enable it to start on boot for CentOS 7 systems.

```bash
sudo yum install ntp ntpdate && \
sudo systemctl start ntpd.service && \
sudo systemctl enable ntpd.service
```

--------------------------------

### Create project directory

Source: https://github.com/pingcap/docs/blob/master/develop/serverless-driver-kysely-example.md

Initializes a new project directory named 'kysely-node-example' and navigates into it.

```bash
mkdir kysely-node-example
cd kysely-node-example
```

--------------------------------

### Create Starter instance with spending limit

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/ticloud-cluster-create.md

Creates a Starter instance with a monthly spending limit specified in USD cents.

```shell
ticloud serverless create --display-name <display-name> --region <region> --spending-limit-monthly <spending-limit-monthly>
```

--------------------------------

### Start a Specific DM Cluster

Source: https://github.com/pingcap/docs/blob/master/dm/deploy-a-dm-cluster-using-tiup-offline.md

Use this command to start the specified DM cluster, for example, 'dm-test'. A successful start is confirmed by the output message 'Started cluster `dm-test` successfully'.

```shell
tiup dm start dm-test
```

--------------------------------

### Example MySQL Client Version Output (Linux)

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-build-cluster-in-cloud.md

This is an example of the expected output when verifying the MySQL client installation on Linux.

```shell
mysql  Ver 15.1 Distrib 5.5.68-MariaDB, for Linux (x86_64) using readline 5.1
```

--------------------------------

### Create and activate a Python virtual environment

Source: https://github.com/pingcap/docs/blob/master/ai/integrations/vector-search-integrate-with-sqlalchemy.md

Navigate to the example directory and set up a new Python virtual environment.

```bash
cd tidb-vector-python/examples/orm-sqlalchemy-quickstart
python3 -m venv .venv
source .venv/bin/activate
```

--------------------------------

### Create table and insert sample data with SQL

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/import-with-mysql-cli-serverless.md

SQL file example that creates a products table and inserts sample data. Use this as a template for preparing your data import.

```sql
-- Create a table in your TiDB database
CREATE TABLE products (
    product_id INT PRIMARY KEY,
    product_name VARCHAR(255),
    price DECIMAL(10, 2)
);

-- Insert sample data into the table
INSERT INTO products (product_id, product_name, price) VALUES
    (1, 'Laptop', 999.99),
    (2, 'Smartphone', 499.99),
    (3, 'Tablet', 299.99);
```

--------------------------------

### Example MySQL Client Version Output (macOS)

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-build-cluster-in-cloud.md

This is an example of the expected output when verifying the MySQL client installation on macOS.

```shell
mysql  Ver 8.0.28 for macos12.0 on arm64 (Homebrew)
```

--------------------------------

### Install multiple TiUP components

Source: https://github.com/pingcap/docs/blob/master/migration-tools.md

This command allows you to install several TiUP components simultaneously, for example, 'dm' and 'tidb-lightning'.

```shell
tiup install dm tidb-lightning
```

--------------------------------

### SQL for Table Creation, Data Insertion, and EXPLAIN Query

Source: https://github.com/pingcap/docs/blob/master/explain-overview.md

Use these SQL commands to set up a sample table, insert data, and then apply EXPLAIN to analyze the execution plan of a SELECT query.

```sql
CREATE TABLE t (id INT NOT NULL PRIMARY KEY auto_increment, a INT NOT NULL, pad1 VARCHAR(255), INDEX(a));
INSERT INTO t VALUES (1, 1, 'aaa'),(2,2, 'bbb');
EXPLAIN SELECT * FROM t WHERE a = 1;
```

--------------------------------

### Example SHOW CREATE TABLE Output

Source: https://github.com/pingcap/docs/blob/master/partitioned-table.md

Verbatim output showing the structure of the 'example' table after partition modifications, including partition names and comments.

```console
*************************** 1. row ***************************
       Table: example
Create Table: CREATE TABLE `example` (
  `id` int NOT NULL,
  `data` varchar(1024) DEFAULT NULL,
  PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin
PARTITION BY HASH (`id`)
(PARTITION `p0`,
 PARTITION `p1`,
 PARTITION `p2`,
 PARTITION `pExample4` COMMENT 'not p3, but pExample4 instead')
1 row in set (0.01 sec)
```

--------------------------------

### Install TiProxy Control using TiUP

Source: https://github.com/pingcap/docs/blob/master/tiproxy/tiproxy-command-line-flags.md

Use TiUP to download and install the binary programs for TiProxy and TiProxy Control. This example also shows how to locate the installed `tiproxyctl` binary.

```shell
tiup install tiproxy
# download https://tiup-mirrors.pingcap.com/tiproxy-v1.3.0-linux-amd64.tar.gz 22.51 MiB / 22.51 MiB 100.00% 13.99 MiB/s
ls `tiup --binary tiproxy`ctl
# /root/.tiup/components/tiproxy/v1.3.0/tiproxyctl
```

--------------------------------

### Netlify Project Initialization Output Example

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/integrate-tidbcloud-with-netlify.md

Illustrative output from netlify init showing site creation, GitHub authorization, and build command configuration.

```shell
Adding local .netlify folder to .gitignore file...
? What would you like to do? +  Create & configure a new site
? Team: your_username’s team
? Site name (leave blank for a random name; you can change it later):

Site Created

Admin URL: https://app.netlify.com/sites/mellow-crepe-e2ca2b
URL:       https://mellow-crepe-e2ca2b.netlify.app
Site ID:   b23d1359-1059-49ed-9d08-ed5dba8e83a2

Linked to mellow-crepe-e2ca2b


? Netlify CLI needs access to your GitHub account to configure Webhooks and Deploy Keys. What would you like to do? Authorize with GitHub through app.netlify.com
Configuring Next.js runtime...

? Your build command (hugo build/yarn run build/etc): npm run netlify-build
? Directory to deploy (blank for current dir): .next

Adding deploy key to repository...
(node:36812) ExperimentalWarning: The Fetch API is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
Deploy key added!

Creating Netlify GitHub Notification Hooks...
Netlify Notification Hooks configured!

Success! Netlify CI/CD Configured!

This site is now configured to automatically deploy from github branches & pull requests

Next steps:

git push       Push to your git repository to trigger new site builds
netlify open   Open the Netlify admin URL of your site
```

--------------------------------

### Example of comments in a table filter file

Source: https://github.com/pingcap/docs/blob/master/table-filter.md

Lines starting with `#` are treated as comments and ignored. A `#` not at the start of a line is considered a syntax error.

```text
# this line is a comment
db.table   # but this part is not comment and may cause error
```

--------------------------------

### TiUP Installation Success Output

Source: https://github.com/pingcap/docs/blob/master/quick-start-with-tidb.md

Example output displayed after a successful TiUP installation, indicating the shell profile path that needs to be sourced.

```log
Successfully set mirror to https://tiup-mirrors.pingcap.com
Detected shell: bash
Shell profile:  /home/user/.bashrc
/home/user/.bashrc has been modified to add tiup to PATH
open a new terminal or source /home/user/.bashrc to use it
Installed path: /home/user/.tiup/bin/tiup
===============================================
Have a try:     tiup playground
===============================================
```

--------------------------------

### Install Prerequisites on CentOS

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-proxysql-integration.md

Install Docker, Git, Python, Docker Compose, and MySQL client on CentOS, then start the Docker service to prepare the environment.

```bash
curl -fsSL https://get.docker.com | bash -s docker
yum install -y git python39 docker-ce docker-ce-cli containerd.io docker-compose-plugin mysql
systemctl start docker
```

--------------------------------

### Install GORM and MySQL Driver for Golang

Source: https://github.com/pingcap/docs/blob/master/develop/dev-guide-choose-driver-or-orm.md

Uses `go get` to install the GORM ORM framework and its MySQL driver for use in a Golang application.

```shell
go get -u gorm.io/gorm
go get -u gorm.io/driver/mysql
```

--------------------------------

### Create Sample Data (Docker MySQL)

Source: https://github.com/pingcap/docs/blob/master/dm/quick-start-with-dm.md

Creates a 'hello' database, a 'hello_tidb' table, inserts sample data, and selects it for verification.

```sql
CREATE DATABASE hello;
USE hello;

CREATE TABLE hello_tidb (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(50)
);

INSERT INTO hello_tidb (name) VALUES ('Hello World');

SELECT * FROM hello_tidb;
```

--------------------------------

### Start Continuous Data Validation with dmctl

Source: https://github.com/pingcap/docs/blob/master/dm/dm-continuous-data-validation.md

Example command to start continuous data validation for a specific DM task (`my_dm_task`) using `dmctl`, specifying the master address, start time, and validation mode.

```shell
dmctl --master-addr=127.0.0.1:8261 validation start --start-time 2021-10-21T00:01:00 --mode full my_dm_task
```

--------------------------------

### Start Kafka Broker Script

Source: https://github.com/pingcap/docs/blob/master/tidb-cloud/setup-azure-self-hosted-kafka-private-link-service.md

Shell script to start Kafka brokers with proper environment setup. Sets JAVA_HOME, Kafka directories, and includes logic to kill any existing Kafka processes before starting new ones.

```shell
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
export JAVA_HOME="$SCRIPT_DIR/jdk-22.0.2"
KAFKA_DIR="$SCRIPT_DIR/kafka_2.13-3.7.1/bin"
KAFKA_STORAGE_CMD=$KAFKA_DIR/kafka-storage.sh
KAFKA_START_CMD=$KAFKA_DIR/kafka-server-start.sh
KAFKA_DATA_DIR=$SCRIPT_DIR/data
KAFKA_LOG_DIR=$SCRIPT_DIR/log
KAFKA_CONFIG_DIR=$SCRIPT_DIR/config

KAFKA_PIDS=$(ps aux | grep 'kafka.Kafka' | grep -v grep | awk '{print $2}')
if [ -z "$KAFKA_PIDS" ]; then
echo "No Kafka processes are running."
else
echo "Killing Kafka processes with PIDs: $KAFKA_PIDS"
for PID in $KAFKA_PIDS; do
    kill -9 $PID
    echo "Killed Kafka process with PID: $PID"
done
```

--------------------------------

### SQL Setup and EXPLAIN with Default Subquery Pre-execution

Source: https://github.com/pingcap/docs/blob/master/explain-walkthrough.md

Creates tables and inserts data, then uses EXPLAIN to show the default behavior where a scalar subquery is pre-executed and its result is used in the plan.

```sql
CREATE TABLE t1(a int);
INSERT INTO t1 VALUES(1);
CREATE TABLE t2(a int);
EXPLAIN SELECT * FROM t2 WHERE a = (SELECT a FROM t1);
```

--------------------------------

### INSERT basic examples with table creation and data insertion

Source: https://github.com/pingcap/docs/blob/master/sql-statements/sql-statement-insert.md

Demonstrates creating tables and inserting rows using various INSERT syntaxes: direct VALUES, column-specified VALUES, and SELECT-based insertion.

```sql
CREATE TABLE t1 (a INT);
```

```sql
CREATE TABLE t2 LIKE t1;
```

```sql
INSERT INTO t1 VALUES (1);
```

```sql
INSERT INTO t1 (a) VALUES (1);
```

```sql
INSERT INTO t2 SELECT * FROM t1;
```

```sql
INSERT INTO t2 VALUES (2),(3),(4);
```

--------------------------------

### Uninstall All TiUP Components

Source: https://github.com/pingcap/docs/blob/master/tiup/tiup-component-management.md

Example of uninstalling all installed TiUP components and their versions.

```shell
tiup uninstall --all
```

--------------------------------

### Clone the pytidb repository

Source: https://github.com/pingcap/docs/blob/master/ai/examples/basic-with-pytidb.md

Clone the `pytidb` repository to get the example code.

```bash
git clone https://github.com/pingcap/pytidb.git
cd pytidb/examples/basic/
```

--------------------------------

### start-task command help

Source: https://github.com/pingcap/docs/blob/master/dm/dm-create-task.md

Display help information for the start-task command including all available flags and options.

```bash
help start-task
```

--------------------------------

### Example Docker Command with Specific Path

Source: https://github.com/pingcap/docs/blob/master/resources/tidb-pdf-generation-tutorial.md

This example shows how to run the Docker image with a specific local documentation path, such as a GitHub repository clone.

```bash
docker run -it -v /Users/${username}/Documents/GitHub/docs:/opt/data andelf/doc-build:0.1.9
```

--------------------------------

### Start Multiple Component Instances

Source: https://github.com/pingcap/docs/blob/master/tiup/tiup-playground.md

Deploy multiple instances of TiDB, TiKV, and PD components. This example starts 3 instances of each component for a larger test cluster.

```bash
tiup playground --db 3 --pd 3 --kv 3
```

--------------------------------

### Create table and insert sample data

Source: https://github.com/pingcap/docs/blob/master/as-of-timestamp.md

Initial setup to create a test table and populate it with sample rows for demonstration purposes.

```sql
create table t (c int);
```

```sql
insert into t values (1), (2), (3);
```

--------------------------------

### Create Sample Data (macOS MySQL)

Source: https://github.com/pingcap/docs/blob/master/dm/quick-start-with-dm.md

Creates a 'hello' database, a 'hello_tidb' table, inserts sample data, and selects it for verification.

```sql
CREATE DATABASE hello;
    USE hello;

    CREATE TABLE hello_tidb (
        id INT AUTO_INCREMENT PRIMARY KEY,
        name VARCHAR(50)
    );

    INSERT INTO hello_tidb (name) VALUES ('Hello World');

    SELECT * FROM hello_tidb;
```

--------------------------------

### TiUP Playground Cluster Start Output

Source: https://github.com/pingcap/docs/blob/master/quick-start-with-tidb.md

Example output after a TiDB Playground cluster successfully starts, providing connection endpoints for TiDB, TiDB Dashboard, and Grafana.

```log
🎉 TiDB Playground Cluster is started, enjoy!

Connect TiDB:    mysql --comments --host 127.0.0.1 --port 4000 -u root
TiDB Dashboard:  http://127.0.0.1:2379/dashboard
Grafana:         http://127.0.0.1:3000
```

--------------------------------

### Successful DM Task Start Output

Source: https://github.com/pingcap/docs/blob/master/dm/migrate-data-using-dm.md

Example JSON response indicating a successful start of a DM data migration task, showing status for individual workers.

```json
{
    "result": true,
    "msg": "",
    "workers": [
        {
            "result": true,
            "worker": "172.16.10.72:8262",
            "msg": ""
        },
        {
            "result": true,
            "worker": "172.16.10.73:8262",
            "msg": ""
        }
    ]
}
```

--------------------------------

### Using USE to select a database and manage tables

Source: https://github.com/pingcap/docs/blob/master/sql-statements/sql-statement-use.md

This example demonstrates how to use the `USE` statement to switch between databases, create a new database, and then create a table within the newly selected database.

```sql
mysql> USE mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> SHOW TABLES;
+-------------------------+
| Tables_in_mysql         |
+-------------------------+
| GLOBAL_VARIABLES        |
| bind_info               |
| columns_priv            |
| db                      |
| default_roles           |
| expr_pushdown_blacklist |
| gc_delete_range         |
| gc_delete_range_done    |
| global_priv             |
| help_topic              |
| opt_rule_blacklist      |
| role_edges              |
| stats_buckets           |
| stats_feedback          |
| stats_histograms        |
| stats_meta              |
| stats_top_n             |
| tables_priv             |
| tidb                    |
| user                    |
+-------------------------+
20 rows in set (0.01 sec)

mysql> CREATE DATABASE newtest;
Query OK, 0 rows affected (0.10 sec)

mysql> USE newtest;
Database changed
mysql> SHOW TABLES;
Empty set (0.00 sec)

mysql> CREATE TABLE t1 (a int);
Query OK, 0 rows affected (0.10 sec)

mysql> SHOW TABLES;
+-------------------+
| Tables_in_newtest |
+-------------------+
| t1                |
+-------------------+
1 row in set (0.00 sec)
```

--------------------------------

### Start systemd user service

Source: https://github.com/pingcap/docs/blob/master/tiup/tiup-cluster-no-sudo-mode.md

Start and verify the systemd user service for the tidb user. Run as root user to get the tidb user ID and manage the service.

```shell
$ uid=$(id -u tidb) # Get the ID of the tidb user
$ systemctl start user@${uid}.service
$ systemctl status user@${uid}.service
user@1000.service - User Manager for UID 1000
Loaded: loaded (/usr/lib/systemd/system/user@.service; static; vendor preset>
Active: active (running) since Mon 2024-01-29 03:30:51 EST; 1min 7s ago
Main PID: 3328 (systemd)
Status: "Startup finished in 420ms."
Tasks: 6
Memory: 6.1M
CGroup: /user.slice/user-1000.slice/user@1000.service
        ├─dbus.service
        │ └─3442 /usr/bin/dbus-daemon --session --address=systemd: --nofork >
        ├─init.scope
        │ ├─3328 /usr/lib/systemd/systemd --user
        │ └─3335 (sd-pam)
        └─pulseaudio.service
          └─3358 /usr/bin/pulseaudio --daemonize=no --log-target=journal
```

--------------------------------

### Interactive Global Binding Setup

Source: https://github.com/pingcap/docs/blob/master/sql-statements/sql-statement-drop-binding.md

This snippet shows an interactive session for creating tables and then establishing several global SQL bindings, including the output from each command.

```sql
> CREATE TABLE t1(a INT, b INT, c INT, INDEX ia(a));
Query OK, 0 rows affected (0.044 sec)

> CREATE TABLE t2(a INT, b INT, c INT, INDEX ia(a));
Query OK, 0 rows affected (0.035 sec)

> CREATE GLOBAL BINDING FOR SELECT * FROM t1 WHERE a > 1 USING SELECT * FROM t1 USE INDEX (ia) WHERE a > 1;
Query OK, 0 rows affected (0.011 sec)

> CREATE GLOBAL BINDING FOR SELECT * FROM t2 WHERE a < 1 USING SELECT * FROM t2 USE INDEX (ia) WHERE a < 1;
Query OK, 0 rows affected (0.013 sec)

> CREATE GLOBAL BINDING FOR SELECT * FROM t1 JOIN t2 ON t1.b = t2.a USING SELECT /*+ HASH_JOIN(t1) */ * FROM t1 JOIN t2 ON t1.b = t2.a;
Query OK, 0 rows affected (0.012 sec)

> SHOW GLOBAL BINDINGS;
```