Standards Considerations Standards Considerations Conventions in the INFORMATION_SCHEMA Reference Sections Related Information • INFORMATION_SCHEMA  queries and the optimizer: Section 8.2.3, “Optimizing INFORMATION_SCHEMA Queries” •Answers to questions that are often asked concerning the  INFORMATION_SCHEMA  database: Section A.7, “MySQL 8.0 FAQ: INFORMATION_SCHEMA” •information about  INFORMATION_SCHEMA  tables specific to the  CONNECTION_CONTROL  plugin: Section 26.6, “INFORMATION_SCHEMA Connection-Control 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  InnoDB  storage engine: Section 26.4, “INFORMATION_SCHEMA InnoDB Tables” These sections discuss additional  INFORMATION_SCHEMA -related topics: 4771 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. •“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. •“ SHOW  Name”  indicates the equivalent field name in the closest  SHOW  statement, if there is one. •“ 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.” The following sections describe each of the tables and columns in  INFORMATION_SCHEMA . For each column, there are three pieces of information: 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. Although other DBMSs use a variety of names, like  syscat  or  system , the standard name is 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. 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 .