- 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 - CHECKSUM TABLE Statement
In case something wrong happens to the database server like if the server was shutdown unexpectedly or, an error occurred while writing data to the hard disk, etc. These situations could make the database operate incorrectly and in the worst case, it can be crashed. Sometimes specific tables will be crushed.
CHECKSUM TABLE Statement
A checksum is a mechanism to detect issues in the table space. The CHECKSUM TABLE Statement is used to report checksum on the specified table. To execute this statement, you need SELECT privilege.
Syntax
Following is the syntax of the MySQL CHECK TABLE Statement −
CHECK TABLE tbl_name [, tbl_name] ... [option] ... option: { FOR UPGRADE | QUICK | FAST | MEDIUM | EXTENDED | CHANGED }
Example
Assume we have created a table named sales as shown below −
CREATE TABLE sales( ID INT, ProductName VARCHAR(255), CustomerName VARCHAR(255), DispatchDate date, DeliveryTime time, Price INT, Location VARCHAR(255) );
Now, we will insert 5 records in Sales table using INSERT statements −
Insert into sales values (1, 'Key-Board', 'Raja', DATE('2019-09-01'), TIME('11:00:00'), 7000, 'Hyderabad'); (2, 'Earphones', 'Roja', DATE('2019-05-01'), TIME('11:00:00'), 2000, 'Vishakhapatnam'); (3, 'Mouse', 'Puja', DATE('2019-03-01'), TIME('10:59:59'), 3000, 'Vijayawada'); (4, 'Mobile', 'Vanaja', DATE('2019-03-01'), TIME('10:10:52'), 9000, 'Chennai'); (5, 'Headset', 'Jalaja', DATE('2019-04-06'), TIME('11:08:59'), 6000, 'Goa');
Following table retrieves the checksum of the above table −
CHECKSUM TABLE Sales;
Output
Following is the output of the above query −
Table | Checksum |
---|---|
mydb.sales | 1059835375 |
Verifying multiple tables
You can also retrieve the ckecksum of multiple tables at once using the CHECKSUM TABLE Statement.
Example
Assume we have created three new tables as shown below −
CREATE TABLE Test1(ID INT, Name VARCHAR(255)); CREATE TABLE Test2(ID INT, Name VARCHAR(255)); CREATE TABLE Test3(ID INT, Name VARCHAR(255));
Following query gets the checksum of all these tables and displays the result −
CHECKSUM TABLE Test1, Test2, Test3;
Output
The above query will generate the Following output −
Table | Checksum |
---|---|
mydb.test1 | 0 |
mydb.test2 | 0 |
mydb.test3 | 0 |
The CHECKSUM TABLE Options
The CHECKSUM TABLE statement provides various optional clauses −
If you specify the QUICK clause in the CHECKSUM TABLE statement, it just checks the incorrect links −
CHECKSUM TABLE sales QUICK;
Output
The above mysql query produces the following output −
Table | Checksum |
---|---|
mydb.sales | NULL |
If you specify the EXTENDED clause in the CHECKSUM TABLE statement, it performs a full check for all keys in each row −
CHECKSUM TABLE sales EXTENDED;
Output
Following is the output of the above query −
Table | Checksum |
---|---|
mydb.sales | 1059835375 |