DROP MATERIALIZED VIEW.md

DROP MATERIALIZED VIEW

功能

该语句用于删除物化视图，删除物化视图为同步操作。

语法

DROP MATERIALIZED VIEW [IF EXISTS] mv_name FROM table_name;

说明：

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。

mv_name

待删除的物化视图的名称。必填项。

table_name

待删除的物化视图所属的表名。必填项。

示例

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 from 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 from 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 from all_type_table;
   Query OK, 0 rows affected (0.00 sec)

   存在则删除，不存在则不报错。