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sql-statement-deallocate.md

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DEALLOCATE
TiDB 数据库中 DEALLOCATE 的使用概况。
/docs-cn/dev/sql-statements/sql-statement-deallocate/
/docs-cn/dev/reference/sql/statements/deallocate/

DEALLOCATE

DEALLOCATE 语句用于为服务器端预处理语句提供 SQL 接口。

语法图

DeallocateStmt ::=
    DeallocateSym 'PREPARE' Identifier

DeallocateSym ::=
    'DEALLOCATE'
|   'DROP'

Identifier ::=
    identifier
|   UnReservedKeyword
|   NotKeywordToken
|   TiDBKeyword

示例

{{< copyable "sql" >}}

PREPARE mystmt FROM 'SELECT ? as num FROM DUAL';
Query OK, 0 rows affected (0.00 sec)

{{< copyable "sql" >}}

SET @number = 5;
Query OK, 0 rows affected (0.00 sec)

{{< copyable "sql" >}}

EXECUTE mystmt USING @number;
+------+
| num  |
+------+
| 5    |
+------+
1 row in set (0.00 sec)

{{< copyable "sql" >}}

DEALLOCATE PREPARE mystmt;
Query OK, 0 rows affected (0.00 sec)

MySQL 兼容性

DEALLOCATE 语句与 MySQL 完全兼容。如发现任何兼容性差异,请在 GitHub 上提交 issue

另请参阅