OceanBase UPDATE
描述
该语句用于修改表中的字段值。
格式
UPDATE [IGNORE] table_references
SET update_asgn_list
[WHERE where_condition]
[ORDER BY order_list]
[LIMIT row_count];
table_references:
tbl_name [PARTITION (partition_name,...)] [, ...]
update_asgn_list:
column_name = expr [, ...]
order_list:
column_name [ASC|DESC] [, column_name [ASC|DESC]…]参数解释
|
参数 |
描述 |
|---|---|
|
IGNORE |
在 INSERT 语句执行过程中发生的错误将会被忽略。 |
|
table_references |
指定修改表名，多表修改时，表名直接‘，’作为间隔。 |
|
where_condition |
指定过滤条件。 |
|
row_count |
限制的行数。 |
|
tbl_name |
插入表名。 |
|
partition_name |
插入表指定的分区名。 |
|
column_name |
列名。 |
|
column_name ASC |
按列名升序修改。 |
|
column_name DESC |
按列名降序修改。 |
注意事项
不管是多表还是单表更新都不支持直接对子查询进行更新值操作，例如：update (select * from t1) set c1 = 100;
示例
- 创建示例表 t1 和 t2。
- 将表 t1 中 "t1.c1=1" 对应的那一行数据的 c2 列值修改为 100。
- 将表 t1 中按照 c2 列排序的前两行数据的 c2 列值修改为 100。
- 将表 t2 中 p2 分区的数据中 "t2.c1 > 2" 的对应行数据的 c2 列值修改为 100。
- 修改多个表。将 t1 表和 t2 表中满足 "t1.c1 = t2.c1" 对应行的数据 t1 表中的 c2 列值修改为 100，t2 表中的 c2 列值修改为 200。
- 修改多个表。修改 t1 表和 t2 表的p2分区中满足 "t1.c1 = t2.c1" 对应行的数据 t1 表中的 c2 列值修改为 100，t2 表中的 c2 列值修改为 200。
- 对可更新视图 v 进行更新值。
OceanBase(admin@test)>create table t1(c1 int primary key, c2 int);
Query OK, 0 rows affected (0.16 sec)
OceanBase(admin@test)>select * from t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
+----+------+
4 rows in set (0.06 sec)
OceanBase(admin@test)>create table t2(c1 int primary key, c2 int) partition by key(c1) partitions 4;
Query OK, 0 rows affected (0.19 sec)
OceanBase(admin@test)>select * from t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
+----+------+
4 rows in set (0.02 sec)OceanBase(admin@test)>update t1 set t1.c2 = 100 where t1.c1 = 1;
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
OceanBase(admin@test)>select * from t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 100 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
+----+------+
4 rows in set (0.01 sec)OceanBase(admin@test)>update t1 set t1.c2 = 100 order by c2 limit 2;
Query OK, 2 rows affected (0.02 sec)
Rows matched: 2 Changed: 2 Warnings: 0
OceanBase(admin@test)>select * from t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 100 |
| 2 | 100 |
| 3 | 3 |
| 4 | 4 |
+----+------+
4 rows in set (0.01 sec)
OceanBase(admin@test)>update t2 partition(p2) set t2.c2 = 100 where t2.c1 > 2;
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
OceanBase(admin@test)>select * from t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
| 1 | 1 |
| 2 | 2 |
| 3 | 100 |
+----+------+
4 rows in set (0.06 sec)OceanBase(admin@test)>update t1,t2 set t1.c2 = 100, t2.c2 = 200 where t1.c2 = t2.c2;
Query OK, 6 rows affected (0.03 sec)
Rows matched: 6 Changed: 6 Warnings: 0
OceanBase(admin@test)>select * from t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 100 |
| 2 | 100 |
| 3 | 100 |
| 4 | 4 |
+----+------+
4 rows in set (0.00 sec)
OceanBase(admin@test)>select * from t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
| 1 | 200 |
| 2 | 200 |
| 3 | 200 |
+----+------+
4 rows in set (0.01 sec)
OceanBase(admin@test)>update t1,t2 partition(p2) set t1.c2 = 100, t2.c2 = 200 where t1.c2 = t2.c2;
Query OK, 6 rows affected (0.02 sec)
Rows matched: 6 Changed: 6 Warnings: 0
OceanBase(admin@test)>select * from t1;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 100 |
| 2 | 100 |
| 3 | 100 |
| 4 | 4 |
+----+------+
4 rows in set (0.01 sec)
OceanBase(admin@test)>select * from t2;
+----+------+
| c1 | c2 |
+----+------+
| 5 | 5 |
| 1 | 200 |
| 2 | 200 |
| 3 | 200 |
+----+------+
4 rows in set (0.01 sec)
OceanBase(admin@test)>create view v as select * from t1;
Query OK, 0 rows affected (0.07 sec)
OceanBase(admin@test)>update v set v.c2 = 100 where v.c1 = 1;
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
OceanBase(admin@test)>select * from v;
+----+------+
| c1 | c2 |
+----+------+
| 1 | 100 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
+----+------+
4 rows in set (0.01 sec)