REPLACE
REPLACE 语句在语义上是一个结合了 DELETE+INSERT 的语句。它可以用来简化应用程序代码。
语法概要
- ReplaceIntoStmt
- PriorityOpt
- IntoOpt
- TableName
- PartitionNameListOpt
- InsertValues
ReplaceIntoStmt ::=
'REPLACE' PriorityOpt IntoOpt TableName PartitionNameListOpt InsertValues
PriorityOpt ::=
( 'LOW_PRIORITY' | 'HIGH_PRIORITY' | 'DELAYED' )?
IntoOpt ::= 'INTO'?
TableName ::=
Identifier ( '.' Identifier )?
PartitionNameListOpt ::=
( 'PARTITION' '(' Identifier ( ',' Identifier )* ')' )?
InsertValues ::=
'(' ( ColumnNameListOpt ')' ( ValueSym ValuesList | SelectStmt | '(' SelectStmt ')' | UnionStmt ) | SelectStmt ')' )
| ValueSym ValuesList
| SelectStmt
| UnionStmt
| 'SET' ColumnSetValue? ( ',' ColumnSetValue )*
示例
mysql> CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, c1 INT NOT NULL);
Query OK, 0 rows affected (0.12 sec)
mysql> INSERT INTO t1 (c1) VALUES (1), (2), (3);
Query OK, 3 rows affected (0.02 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> SELECT * FROM t1;
+----+----+
| id | c1 |
+----+----+
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
+----+----+
3 rows in set (0.00 sec)
mysql> REPLACE INTO t1 (id, c1) VALUES(3, 99);
Query OK, 2 rows affected (0.01 sec)
mysql> SELECT * FROM t1;
+----+----+
| id | c1 |
+----+----+
| 1 | 1 |
| 2 | 2 |
| 3 | 99 |
+----+----+
3 rows in set (0.00 sec)
MySQL 兼容性
TiDB 中的 REPLACE 语句与 MySQL 完全兼容。如果你发现任何兼容性差异，请报告一个 bug。