## Standards Considerations 

The implementation for the INFORMATION_SCHEMA  table structures in MySQL follows the ANSI/ISO SQL:2003 standard Part 11 Schemata . Our intent is approximate compliance with SQL:2003 core feature F021 Basic information schema . 

Users of SQL Server 2000 (which also follows the standard) may notice a strong similarity. However, MySQL has omitted many columns that are not relevant for our implementation, and added columns that are MySQL-specific. One such added column is the ENGINE  column in the INFORMATION_SCHEMA TABLES  table. 

Although other DBMSs use a variety of names, like syscat  or system , the standard name is INFORMATION_SCHEMA . 

To avoid using any name that is reserved in the standard or in DB2, SQL Server, or Oracle, we changed the names of some columns marked “MySQL extension” . (For example, we changed COLLATION  to TABLE_COLLATION  in the TABLES  table.) See the list of reserved words near the end of this article: https://web.archive.org/web/20070428032454/http://www.dbazine.com/db2/db2-disarticles/gulutzan5. 

## Conventions in the INFORMATION_SCHEMA Reference Sections 

The following sections describe each of the tables and columns in INFORMATION_SCHEMA . For each column, there are three pieces of information: 

•“ INFORMATION_SCHEMA  Name”  indicates the name for the column in the INFORMATION_SCHEMA  table. This corresponds to the standard SQL name unless the “Remarks”  field says “MySQL extension.” 

•“ SHOW  Name”  indicates the equivalent field name in the closest SHOW  statement, if there is one. 

•“Remarks”  provides additional information where applicable. If this field is NULL , it means that the value of the column is always NULL . If this field says “MySQL extension,”  the column is a MySQL extension to standard SQL. 

Many sections indicate what SHOW  statement is equivalent to a SELECT  that retrieves information from INFORMATION_SCHEMA . For SHOW  statements that display information for the default database if you omit a FROM db_name  clause, you can often select information for the default database by adding an AND TABLE_SCHEMA = SCHEMA()  condition to the WHERE  clause of a query that retrieves information from an INFORMATION_SCHEMA  table. 

## Related Information 

These sections discuss additional INFORMATION_SCHEMA -related topics: 

•information about INFORMATION_SCHEMA  tables specific to the InnoDB  storage engine: Section 26.4, “INFORMATION_SCHEMA InnoDB Tables” 

•information about INFORMATION_SCHEMA  tables specific to the thread pool plugin: Section 26.5, “INFORMATION_SCHEMA Thread Pool Tables” 

•information about INFORMATION_SCHEMA  tables specific to the CONNECTION_CONTROL  plugin: Section 26.6, “INFORMATION_SCHEMA Connection-Control Tables” 

•Answers to questions that are often asked concerning the INFORMATION_SCHEMA  database: Section A.7, “MySQL 8.0 FAQ: INFORMATION_SCHEMA” 

• INFORMATION_SCHEMA  queries and the optimizer: Section 8.2.3, “Optimizing INFORMATION_SCHEMA Queries” 

