MySQL - Identifiers

This article describes identifiers in MySQL.

Identifiers rules

MySQL - Identifier
First Character	An alphanumeric character
Subsequent Characters	Alphanumeric characters, the underscore (_), dollar sign ($)
Maximum Length	64 bytes Alias names are limited to 255 bytes
Case Sensitivity	Identifiers are not case sensitive for MySQL on Windows, and case sensitive for MySQL on Unix. Trigger names are case sensitive not depending on the platform
Standards	ANSI SQL - $ is not allowed

Identifiers - Differences between MySQL and other Databases

Database	Identifiers	First Character	Subsequent Characters	Max Length
Oracle	Oracle Identifiers	Not allowed: digit	Allowed: #	30
SQL Server	SQL Server Identifiers	Not allowed: digit Allowed: _, @ and #	Allowed: # and @	128
IBM DB2	IBM DB2 Identifiers	Not allowed: digit	Not allowed: $	128
PostgreSQL	PostgreSQL Identifiers	Not allowed: digit Allowed: _	No differences	63
Sybase ASE	Sybase ASE Identifiers	Not allowed: digit Allowed: _ , @ and #	Allowed: # and @	255
Sybase ASA	Sybase ASA Identifiers	Not allowed: digit Allowed: _ , $, @ and #	Allowed: # and @	128
Informix	Informix Identifiers	Not allowed: digit Allowed: _	No differences	128
Teradata	Teradata Identifiers	Not allowed: digit Allowed: _, $ and #	Allowed: #	30
HP Neoview	HP Neoview Identifiers	Not allowed: digit	Not allowed: $	128
Interbase/Firebird	Interbase/Firebird Identifiers	Not allowed: digit	No differences	67

MySQL - Quoted Identifiers
Quotation Marks	Back tick (``)
Characters	Any character except ASCII 0(0x00) or a byte with the value of 255 and the space in the end of database, table and column names
Maximum Length	64 bytes not including quotes
Case Sensitivity	Case sensitive
Notes	When ANSI_QUOTES SQL mode is enabled it is also allowed to use double quotes (“”) to quote identifiers.

Quoted Identifiers - Differences between MySQL and other Databases

Database	Identifiers	Quotation Marks	Characters	Case Sensitivity
Oracle	Oracle Quoted Identifiers	“”	Any except quotes	Case sensitive
SQL Server	SQL Server Quoted Identifiers	[] and “”	Any except quotes	Case insensitive
IBM DB2	IBM DB2 Quoted Identifiers	“”	Any including quotes	Case sensitive
PostgreSQL	PostgreSQL Quoted Identifiers	“”	Any including quotes	Case sensitive
Sybase ASE	Sybase ASE Quoted Identifiers	[] and “”	Any except pound sign (#) as the first character	Case insensitive
Sybase ASA	Sybase ASA Quoted Identifiers	[] and “”	Any	Case insensitive
Informix	Informix Quoted Identifiers	“”	Any including quotes	Case sensitive
Teradata	Teradata Quoted Identifiers	“”	Any including quotes	Case insensitive
HP Neoview	HP Neoview Quoted Identifiers	“”	Any except at sign (@), forward slash (/), circumflex character (^) as the first character and space(s) as the last character(s)	Case sensitive
Interbase/Firebird	Interbase/Firebird Quoted Identifiers	“”	Any character except space(s) as the last character(s)	Case sensitive