# DROP MATERIALIZED VIEW ## description 该语句用于删除物化视图。同步语法 语法: ``` DROP MATERIALIZED VIEW [IF EXISTS] mv_name ON table_name ``` 1. IF EXISTS 如果物化视图不存在，不要抛出错误。如果不声明此关键字，物化视图不存在则报错。 2. mv_name 待删除的物化视图的名称。必填项。 3. table_name 待删除的物化视图所属的表名。必填项。 ## example 表结构为 ``` mysql> desc all_type_table all; +----------------+-------+----------+------+-------+---------+-------+ | IndexName | Field | Type | Null | Key | Default | Extra | +----------------+-------+----------+------+-------+---------+-------+ | all_type_table | k1 | TINYINT | Yes | true | N/A | | | | k2 | SMALLINT | Yes | false | N/A | NONE | | | k3 | INT | Yes | false | N/A | NONE | | | k4 | BIGINT | Yes | false | N/A | NONE | | | k5 | LARGEINT | Yes | false | N/A | NONE | | | k6 | FLOAT | Yes | false | N/A | NONE | | | k7 | DOUBLE | Yes | false | N/A | NONE | | | | | | | | | | k1_sumk2 | k1 | TINYINT | Yes | true | N/A | | | | k2 | SMALLINT | Yes | false | N/A | SUM | +----------------+-------+----------+------+-------+---------+-------+ ``` 1. 删除表 all_type_table 的名为 k1_sumk2 的物化视图 ``` drop materialized view k1_sumk2 on all_type_table; ``` 物化视图被删除后的表结构 ``` +----------------+-------+----------+------+-------+---------+-------+ | IndexName | Field | Type | Null | Key | Default | Extra | +----------------+-------+----------+------+-------+---------+-------+ | all_type_table | k1 | TINYINT | Yes | true | N/A | | | | k2 | SMALLINT | Yes | false | N/A | NONE | | | k3 | INT | Yes | false | N/A | NONE | | | k4 | BIGINT | Yes | false | N/A | NONE | | | k5 | LARGEINT | Yes | false | N/A | NONE | | | k6 | FLOAT | Yes | false | N/A | NONE | | | k7 | DOUBLE | Yes | false | N/A | NONE | +----------------+-------+----------+------+-------+---------+-------+ ``` 2. 删除表 all_type_table 中一个不存在的物化视图 ``` drop materialized view k1_k2 on all_type_table; ERROR 1064 (HY000): errCode = 2, detailMessage = Materialized view [k1_k2] does not exist in table [all_type_table] ``` 删除请求直接报错 3. 删除表 all_type_table 中的物化视图 k1_k2，不存在不报错。 ``` drop materialized view if exists k1_k2 on all_type_table; Query OK, 0 rows affected (0.00 sec) ``` 存在则删除，不存在则不报错。 ## keyword DROP, MATERIALIZED, VIEW