Identifier Length Limits If the  ANSI_QUOTES  SQL mode is enabled, it is also permissible to quote identifiers within double quotation marks: The  ANSI_QUOTES  mode causes the server to interpret double-quoted strings as identifiers. Consequently, when this mode is enabled, string literals must be enclosed within single quotation marks. They cannot be enclosed within double quotation marks. The server SQL mode is controlled as described in Section 5.1.11, “Server SQL Modes” . Identifier quote characters can be included within an identifier if you quote the identifier. If the character to be included within the identifier is the same as that used to quote the identifier itself, then you need to double the character. The following statement creates a table named  a‘b  that contains a column named c"d : In the select list of a query, a quoted column alias can be specified using identifier or string quoting characters: Elsewhere in the statement, quoted references to the alias must use identifier quoting or the reference is treated as a string literal. It is recommended that you do not use names that begin with  M e  or  M e N , where  M  and  N  are integers. For example, avoid using  1e  as an identifier, because an expression such as  1e+3  is ambiguous. Depending on context, it might be interpreted as the expression  1e + 3  or as the number  1e+3 . Be careful when using  MD5()  to produce table names because it can produce names in illegal or ambiguous formats such as those just described. A user variable cannot be used directly in an SQL statement as an identifier or as part of an identifier. See Section 9.4, “User-Defined Variables” , for more information and examples of workarounds. Special characters in database and table names are encoded in the corresponding file system names as described in Section 9.2.4, “Mapping of Identifiers to File Names” . The following table describes the maximum length for each type of identifier. 9.2.1 Identifier Length Limits 1870 Identifier Type Maximum Length (characters) Database 64 (includes NDB Cluster 8.0.18 and later) Table 64 (includes NDB Cluster 8.0.18 and later) Column 64 Index 64 Constraint 64 mysql>  SELECT 1 AS ‘one‘, 2 AS ’two’; mysql>  CREATE TABLE ‘a‘‘b‘ (‘c"d‘ INT); mysql>  CREATE TABLE "test" (col INT); ERROR 1064: You have an error in your SQL syntax... mysql>  SET sql_mode=’ANSI_QUOTES’; mysql>  CREATE TABLE "test" (col INT); Query OK, 0 rows affected (0.00 sec) +-----+-----+ | one | two | +-----+-----+ | 1 | 2 | +-----+-----+