9.3 Reserved Words

Certain words such as SELECT, DELETE, or BIGINT are reserved and require special treatment for use as identifiers such as table and column names. This may also be true for the names of built-in functions.

Reserved words are permitted as identifiers if you quote them as described in Section 9.2, “Schema Object Names”:

mysql> CREATE TABLE interval (begin INT, end INT);
ERROR 1064 (42000): You have an error in your SQL syntax ...
near 'interval (begin INT, end INT)'

mysql> CREATE TABLE `interval` (begin INT, end INT);
Query OK, 0 rows affected (0.01 sec)

Exception: A word that follows a period in a qualified name must be an identifier, so it need not be quoted even if it is reserved:

mysql> CREATE TABLE mydb.interval (begin INT, end INT);
Query OK, 0 rows affected (0.01 sec)

Names of built-in functions are permitted as identifiers but may require care to be used as such. For example, COUNT is acceptable as a column name. However, by default, no whitespace is permitted in function invocations between the function name and the following ( character. This requirement enables the parser to distinguish whether the name is used in a function call or in nonfunction context. For further detail on recognition of function names, see Section 9.2.4, “Function Name Parsing and Resolution”.

The words in the following table are explicitly reserved in MySQL 5.6. In addition, _FILENAME is reserved. At some point, you might upgrade to a higher version, so it is a good idea to have a look at future reserved words, too. You can find these in the manuals that cover higher versions of MySQL. Most of the words in the table are forbidden by standard SQL as column or table names (for example, GROUP). A few are reserved because MySQL needs them and uses a yacc parser. A reserved word can be used as an identifier if you quote it.

For a more detailed list of reserved words, including differences between versions, see Reserved Words in MySQL 5.6.

Table 9.2 Reserved Words in MySQL 5.6.23

ACCESSIBLEADDALL
ALTERANALYZEAND
ASASCASENSITIVE
BEFOREBETWEENBIGINT
BINARYBLOBBOTH
BYCALLCASCADE
CASECHANGECHAR
CHARACTERCHECKCOLLATE
COLUMNCONDITIONCONSTRAINT
CONTINUECONVERTCREATE
CROSSCURRENT_DATECURRENT_TIME
CURRENT_TIMESTAMPCURRENT_USERCURSOR
DATABASEDATABASESDAY_HOUR
DAY_MICROSECONDDAY_MINUTEDAY_SECOND
DECDECIMALDECLARE
DEFAULTDELAYEDDELETE
DESCDESCRIBEDETERMINISTIC
DISTINCTDISTINCTROWDIV
DOUBLEDROPDUAL
EACHELSEELSEIF
ENCLOSEDESCAPEDEXISTS
EXITEXPLAINFALSE
FETCHFLOATFLOAT4
FLOAT8FORFORCE
FOREIGNFROMFULLTEXT
GETGRANTGROUP
HAVINGHIGH_PRIORITYHOUR_MICROSECOND
HOUR_MINUTEHOUR_SECONDIF
IGNOREININDEX
INFILEINNERINOUT
INSENSITIVEINSERTINT
INT1INT2INT3
INT4INT8INTEGER
INTERVALINTOIO_AFTER_GTIDS
IO_BEFORE_GTIDSISITERATE
JOINKEYKEYS
KILLLEADINGLEAVE
LEFTLIKELIMIT
LINEARLINESLOAD
LOCALTIMELOCALTIMESTAMPLOCK
LONGLONGBLOBLONGTEXT
LOOPLOW_PRIORITYMASTER_BIND
MASTER_SSL_VERIFY_SERVER_CERTMATCHMAXVALUE
MEDIUMBLOBMEDIUMINTMEDIUMTEXT
MIDDLEINTMINUTE_MICROSECONDMINUTE_SECOND
MODMODIFIESNATURAL
NOTNO_WRITE_TO_BINLOGNULL
NUMERICONOPTIMIZE
OPTIONOPTIONALLYOR
ORDEROUTOUTER
OUTFILEPARTITIONPRECISION
PRIMARYPROCEDUREPURGE
RANGEREADREADS
READ_WRITEREALREFERENCES
REGEXPRELEASERENAME
REPEATREPLACEREQUIRE
RESIGNALRESTRICTRETURN
REVOKERIGHTRLIKE
SCHEMASCHEMASSECOND_MICROSECOND
SELECTSENSITIVESEPARATOR
SETSHOWSIGNAL
SMALLINTSPATIALSPECIFIC
SQLSQLEXCEPTIONSQLSTATE
SQLWARNINGSQL_BIG_RESULTSQL_CALC_FOUND_ROWS
SQL_SMALL_RESULTSSLSTARTING
STRAIGHT_JOINTABLETERMINATED
THENTINYBLOBTINYINT
TINYTEXTTOTRAILING
TRIGGERTRUEUNDO
UNIONUNIQUEUNLOCK
UNSIGNEDUPDATEUSAGE
USEUSINGUTC_DATE
UTC_TIMEUTC_TIMESTAMPVALUES
VARBINARYVARCHARVARCHARACTER
VARYINGWHENWHERE
WHILEWITHWRITE
XORYEAR_MONTHZEROFILL

Table 9.3 New Reserved Words in MySQL 5.6

GETIO_AFTER_GTIDSIO_BEFORE_GTIDS
MASTER_BINDONE_SHOTPARTITION
SQL_AFTER_GTIDSSQL_BEFORE_GTIDS 

MySQL permits some keywords to be used as unquoted identifiers because many people previously used them. Examples are those in the following list: