关键字和保留字

关键字和保留字

关键字在 SQL 中有特殊的意义，例如 SELECT，UPDATE，DELETE，在作为表名跟函数名的时候，需要特殊对待，例如作为表名，保留字需要被反引号包住：

mysql> CREATE TABLE select (a INT);
ERROR 1105 (HY000): line 0 column 19 near " (a INT)" (total length 27)
mysql> CREATE TABLE `select` (a INT);
Query OK, 0 rows affected (0.09 sec)

BEGIN 和 END 是关键字，但不是保留字，所以不需要反引号：

mysql> CREATE TABLE `select` (BEGIN int, END int);
Query OK, 0 rows affected (0.09 sec)

有一种特殊情况，如果使用了限定符 .，那么也不需要用反引号：

mysql> CREATE TABLE test.select (BEGIN int, END int);
Query OK, 0 rows affected (0.08 sec)

下表列出了在 TiDB 中的关键字跟保留字，保留字用 (R) 来标识：

ACTION	ADD (R)	ADDDATE
ADMIN	AFTER	ALL (R)
ALTER (R)	ALWAYS	ANALYZE(R)
AND (R)	ANY	AS (R)
ASC (R)	ASCII	AUTO_INCREMENT
AVG	AVG_ROW_LENGTH	BEGIN
BETWEEN (R)	BIGINT (R)	BINARY (R)
BINLOG	BIT	BIT_XOR
BLOB (R)	BOOL	BOOLEAN
BOTH (R)	BTREE	BY (R)
BYTE	CASCADE (R)	CASE (R)
CAST	CHANGE (R)	CHAR (R)
CHARACTER (R)	CHARSET	CHECK (R)
CHECKSUM	COALESCE	COLLATE (R)
COLLATION	COLUMN (R)	COLUMNS
COMMENT	COMMIT	COMMITTED
COMPACT	COMPRESSED	COMPRESSION
CONNECTION	CONSISTENT	CONSTRAINT (R)
CONVERT (R)	COUNT	CREATE (R)
CROSS (R)	CURRENT_DATE (R)	CURRENT_TIME (R)
CURRENT_TIMESTAMP (R)	CURRENT_USER (R)	CURTIME
DATA	DATABASE (R)	DATABASES (R)
DATE	DATE_ADD	DATE_SUB
DATETIME	DAY	DAY_HOUR (R)
DAY_MICROSECOND (R)	DAY_MINUTE (R)	DAY_SECOND (R)
DDL	DEALLOCATE	DEC
DECIMAL (R)	DEFAULT (R)	DELAY_KEY_WRITE
DELAYED (R)	DELETE (R)	DESC (R)
DESCRIBE (R)	DISABLE	DISTINCT (R)
DISTINCTROW (R)	DIV (R)	DO
DOUBLE (R)	DROP (R)	DUAL (R)
DUPLICATE	DYNAMIC	ELSE (R)
ENABLE	ENCLOSED	END
ENGINE	ENGINES	ENUM
ESCAPE	ESCAPED	EVENTS
EXCLUSIVE	EXECUTE	EXISTS
EXPLAIN (R)	EXTRACT	FALSE (R)
FIELDS	FIRST	FIXED
FLOAT (R)	FLUSH	FOR (R)
FORCE (R)	FOREIGN (R)	FORMAT
FROM (R)	FULL	FULLTEXT (R)
FUNCTION	GENERATED (R)	GET_FORMAT
GLOBAL	GRANT (R)	GRANTS
GROUP (R)	GROUP_CONCAT	HASH
HAVING (R)	HIGH_PRIORITY (R)	HOUR
HOUR_MICROSECOND (R)	HOUR_MINUTE (R)	HOUR_SECOND (R)
IDENTIFIED	IF (R)	IGNORE (R)
IN (R)	INDEX (R)	INDEXES
INFILE (R)	INNER (R)	INSERT (R)
INT (R)	INTEGER (R)	INTERVAL (R)
INTO (R)	IS (R)	ISOLATION
JOBS	JOIN (R)	JSON
KEY (R)	KEY_BLOCK_SIZE	KEYS (R)
KILL (R)	LEADING (R)	LEFT (R)
LESS	LEVEL	LIKE (R)
LIMIT (R)	LINES (R)	LOAD (R)
LOCAL	LOCALTIME (R)	LOCALTIMESTAMP (R)
LOCK (R)	LONGBLOB (R)	LONGTEXT (R)
LOW_PRIORITY (R)	MAX	MAX_ROWS
MAXVALUE (R)	MEDIUMBLOB (R)	MEDIUMINT (R)
MEDIUMTEXT (R)	MICROSECOND	MIN
MIN_ROWS	MINUTE	MINUTE_MICROSECOND (R)
MINUTE_SECOND (R)	MIN	MIN_ROWS
MINUTE	MINUTE_MICROSECOND	MINUTE_SECOND
MOD (R)	MODE	MODIRY
MONTH	NAMES	NATIONAL
NATURAL (R)	NO	NO_WRITE_TO_BINLOG (R)
NONE	NOT (R)	NOW
NULL (R)	NUMERIC (R)	NVARCHAR (R)
OFFSET	ON (R)	ONLY
OPTION (R)	OR (R)	ORDER (R)
OUTER (R)	PARTITION (R)	PARTITIONS
PASSWORD	PLUGINS	POSITION
PRECISION (R)	PREPARE	PRIMARY (R)
PRIVILEGES	PROCEDURE (R)	PROCESS
PROCESSLIST	QUARTER	QUERY
QUICK	RANGE (R)	READ (R)
REAL (R)	REDUNDANT	REFERENCES (R)
REGEXP (R)	RENAME (R)	REPEAT (R)
REPEATABLE	REPLACE (R)	RESTRICT (R)
REVERSE	REVOKE (R)	RIGHT (R)
RLIKE (R)	ROLLBACK	ROW
ROW_COUNT	ROW_FORMAT	SCHEMA
SCHEMAS	SECOND	SECOND_MICROSECOND (R)
SELECT (R)	SERIALIZABLE	SESSION
SET (R)	SHARE	SHARED
SHOW (R)	SIGNED	SMALLINT (R)
SNAPSHOT	SOME	SQL_CACHE
SQL_CALC_FOUND_ROWS (R)	SQL_NO_CACHE	START
STARTING (R)	STATS	STATS_BUCKETS
STATS_HISTOGRAMS	STATS_META	STATS_PERSISTENT
STATUS	STORED (R)	SUBDATE
SUBSTR	SUBSTRING	SUM
SUPER	TABLE (R)	TABLES
TERMINATED (R)	TEXT	THAN
THEN (R)	TIDB	TIDB_INLJ
TIDB_SMJ	TIME	TIMESTAMP
TIMESTAMPADD	TIMESTAMPDIFF	TINYBLOB (R)
TINYINT (R)	TINYTEXT (R)	TO (R)
TRAILING (R)	TRANSACTION	TRIGGER (R)
TRIGGERS	TRIM	TRUE (R)
TRUNCATE	UNCOMMITTED	UNION (R)
UNIQUE (R)	UNKNOWN	UNLOCK (R)
UNSIGNED (R)	UPDATE (R)	USE (R)
USER	USING (R)	UTC_DATE (R)
UTC_TIME (R)	UTC_TIMESTAMP (R)	VALUE
VALUES (R)	VARBINARY (R)	VARCHAR (R)
VARIABLES	VIEW	VIRTUAL (R)
WARNINGS	WEEK	WHEN (R)
WHERE (R)	WITH (R)	WRITE (R)
XOR (R)	YEAR	YEAR_MONTH (R)
ZEROFILL (R)