- MySQL Basics
- MySQL - Home
- MySQL - Introduction
- MySQL - Features
- MySQL - Versions
- MySQL - Variables
- MySQL - Installation
- MySQL - Administration
- MySQL - PHP Syntax
- MySQL - Node.js Syntax
- MySQL - Java Syntax
- MySQL - Python Syntax
- MySQL - Connection
- MySQL - Workbench
- MySQL Databases
- MySQL - Create Database
- MySQL - Drop Database
- MySQL - Select Database
- MySQL - Show Database
- MySQL - Copy Database
- MySQL - Database Export
- MySQL - Database Import
- MySQL - Database Info
- MySQL Users
- MySQL - Create Users
- MySQL - Drop Users
- MySQL - Show Users
- MySQL - Change Password
- MySQL - Grant Privileges
- MySQL - Show Privileges
- MySQL - Revoke Privileges
- MySQL - Lock User Account
- MySQL - Unlock User Account
- MySQL Tables
- MySQL - Create Tables
- MySQL - Show Tables
- MySQL - Alter Tables
- MySQL - Rename Tables
- MySQL - Clone Tables
- MySQL - Truncate Tables
- MySQL - Temporary Tables
- MySQL - Repair Tables
- MySQL - Describe Tables
- MySQL - Add/Delete Columns
- MySQL - Show Columns
- MySQL - Rename Columns
- MySQL - Table Locking
- MySQL - Drop Tables
- MySQL - Derived Tables
- MySQL Queries
- MySQL - Queries
- MySQL - Constraints
- MySQL - Insert Query
- MySQL - Select Query
- MySQL - Update Query
- MySQL - Delete Query
- MySQL - Replace Query
- MySQL - Insert Ignore
- MySQL - Insert on Duplicate Key Update
- MySQL - Insert Into Select
- MySQL Indexes
- MySQL - Indexes
- MySQL - Create Index
- MySQL - Drop Index
- MySQL - Show Indexes
- MySQL - Unique Index
- MySQL - Clustered Index
- MySQL - Non-Clustered Index
- MySQL Operators and Clauses
- MySQL - Where Clause
- MySQL - Limit Clause
- MySQL - Distinct Clause
- MySQL - Order By Clause
- MySQL - Group By Clause
- MySQL - Having Clause
- MySQL - AND Operator
- MySQL - OR Operator
- MySQL - Like Operator
- MySQL - IN Operator
- MySQL - ANY Operator
- MySQL - EXISTS Operator
- MySQL - NOT Operator
- MySQL - NOT EQUAL Operator
- MySQL - IS NULL Operator
- MySQL - IS NOT NULL Operator
- MySQL - Between Operator
- MySQL - UNION Operator
- MySQL - UNION vs UNION ALL
- MySQL - MINUS Operator
- MySQL - INTERSECT Operator
- MySQL - INTERVAL Operator
- MySQL Joins
- MySQL - Using Joins
- MySQL - Inner Join
- MySQL - Left Join
- MySQL - Right Join
- MySQL - Cross Join
- MySQL - Full Join
- MySQL - Self Join
- MySQL - Delete Join
- MySQL - Update Join
- MySQL - Union vs Join
- MySQL Keys
- MySQL - Unique Key
- MySQL - Primary Key
- MySQL - Foreign Key
- MySQL - Composite Key
- MySQL - Alternate Key
- MySQL Triggers
- MySQL - Triggers
- MySQL - Create Trigger
- MySQL - Show Trigger
- MySQL - Drop Trigger
- MySQL - Before Insert Trigger
- MySQL - After Insert Trigger
- MySQL - Before Update Trigger
- MySQL - After Update Trigger
- MySQL - Before Delete Trigger
- MySQL - After Delete Trigger
- MySQL Data Types
- MySQL - Data Types
- MySQL - VARCHAR
- MySQL - BOOLEAN
- MySQL - ENUM
- MySQL - DECIMAL
- MySQL - INT
- MySQL - FLOAT
- MySQL - BIT
- MySQL - TINYINT
- MySQL - BLOB
- MySQL - SET
- MySQL Regular Expressions
- MySQL - Regular Expressions
- MySQL - RLIKE Operator
- MySQL - NOT LIKE Operator
- MySQL - NOT REGEXP Operator
- MySQL - regexp_instr() Function
- MySQL - regexp_like() Function
- MySQL - regexp_replace() Function
- MySQL - regexp_substr() Function
- MySQL Fulltext Search
- MySQL - Fulltext Search
- MySQL - Natural Language Fulltext Search
- MySQL - Boolean Fulltext Search
- MySQL - Query Expansion Fulltext Search
- MySQL - ngram Fulltext Parser
- MySQL Functions & Operators
- MySQL - Date and Time Functions
- MySQL - Arithmetic Operators
- MySQL - Numeric Functions
- MySQL - String Functions
- MySQL - Aggregate Functions
- MySQL Misc Concepts
- MySQL - NULL Values
- MySQL - Transactions
- MySQL - Using Sequences
- MySQL - Handling Duplicates
- MySQL - SQL Injection
- MySQL - SubQuery
- MySQL - Comments
- MySQL - Check Constraints
- MySQL - Storage Engines
- MySQL - Export Table into CSV File
- MySQL - Import CSV File into Database
- MySQL - UUID
- MySQL - Common Table Expressions
- MySQL - On Delete Cascade
- MySQL - Upsert
- MySQL - Horizontal Partitioning
- MySQL - Vertical Partitioning
- MySQL - Cursor
- MySQL - Stored Functions
- MySQL - Signal
- MySQL - Resignal
- MySQL - Character Set
- MySQL - Collation
- MySQL - Wildcards
- MySQL - Alias
- MySQL - ROLLUP
- MySQL - Today Date
- MySQL - Literals
- MySQL - Stored Procedure
- MySQL - Explain
- MySQL - JSON
- MySQL - Standard Deviation
- MySQL - Find Duplicate Records
- MySQL - Delete Duplicate Records
- MySQL - Select Random Records
- MySQL - Show Processlist
- MySQL - Change Column Type
- MySQL - Reset Auto-Increment
- MySQL - Coalesce() Function
MySQL - HELP Statement
MySQL HELP Statement
The HELP statement is used to retrieve the information from the MySQL official documentation about the specified string.
Syntax
Following is the HELP statement −
HELP 'search_string'
Example
Following query retrieves the list of contents of the MySQL online documentation −
HELP 'contents' You asked for help about help category: "Contents" For more information, type 'help <item>', where <item> is one of the following categories: Account Management Administration Components Compound Statements Contents Data Definition Data Manipulation Data Types Functions Geographic Features Help Metadata Language Structure Plugins Storage Engines Table Maintenance Transactions User-Defined Functions Utility
Following query retrieves the list of datatypes of the MySQL database specified in the official online documentation −
HELP 'data types' You asked for help about help category: "Data Types" For more information, type 'help <item>', where <item> is one of the following topics: AUTO_INCREMENT BIGINT BINARY BIT BLOB BLOB DATA TYPE BOOLEAN CHAR CHAR BYTE DATE DATETIME DEC DECIMAL DOUBLE DOUBLE PRECISION ENUM FLOAT INT INTEGER LONGBLOB LONGTEXT MEDIUMBLOB MEDIUMINT MEDIUMTEXT SET DATA TYPE SMALLINT TEXT TIME TIMESTAMP TINYBLOB TINYINT TINYTEXT VARBINARY VARCHAR YEAR DATA TYPE
You can also get the documentation of an in-built function by specifying the name of the function as the search_string, as shown below −
Name: 'LCASE' Description: Syntax: LCASE(str) LCASE() is a synonym for LOWER(). URL: https://dev.mysql.com/doc/refman/8.0/en/string-functions.html
Following query retrieves the information about the USE query −
help 'use' Name: 'USE' Description: Syntax: USE db_name The USE statement tells MySQL to use the named database as the default (current) database for subsequent statements. This statement requires some privilege for the database or some object within it. The named database remains the default until the end of the session or another USE statement is issued: USE db1; SELECT COUNT(*) FROM mytable; # selects from db1.mytable USE db2; SELECT COUNT(*) FROM mytable; # selects from db2.mytable The database name must be specified on a single line. Newlines in database names are not supported. URL: https://dev.mysql.com/doc/refman/8.0/en/use.html
Following query retrieves the list of functions of the MySQL database specified in the official online documentation −
help 'functions' You asked for help about help category: "Functions" For more information, type 'help <item>', where <item> is one of the following categories: Aggregate Functions and Modifiers Bit Functions Cast Functions and Operators Comparison Operators Control Flow Functions Date and Time Functions Encryption Functions Enterprise Encryption Functions GROUP BY Functions and Modifiers GTID Information Functions Internal Functions Locking Functions Logical Operators Miscellaneous Functions Numeric Functions Performance Schema Functions Spatial Functions String Functions Window Functions XML
Advertisements