PostgreSQL UPDATE 查询用于修改表中的现有记录.您可以将WHERE子句与UPDATE查询一起使用来更新所选行.否则,所有行都将被更新.
使用WHERE子句的UPDATE查询的基本语法如下 :
UPDATE table_name SET column1 = value1,column2 = value2 ....,columnN = valueN WHERE [condition];
您可以使用AND或OR运算符组合N个条件.
考虑表格公司,记录如下 :
testdb# select * from COMPANY; id | name | age | address | salary ----+-------+-----+-----------+-------- 1 | Paul | 32 | California| 20000 2 | Allen | 25 | Texas | 15000 3 | Teddy | 23 | Norway | 20000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall| 45000 7 | James | 24 | Houston | 10000 (7 rows)
以下是一个示例,它将为客户更新ADDRESS,其ID为6 :
testdb=# UPDATE COMPANY SET SALARY = 15000 WHERE ID = 3;
现在,COMPANY表将有以下记录 :
id | name | age | address | salary ----+-------+-----+------------+-------- 1 | Paul | 32 | California | 20000 2 | Allen | 25 | Texas | 15000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall | 45000 7 | James | 24 | Houston | 10000 3 | Teddy | 23 | Norway | 15000 (7 rows)
如果要修改COMPANY表中的所有ADDRESS和SALARY列值,则不需要使用WHERE子句和UPDATE查询如下 :
testdb=# UPDATE COMPANY SET ADDRESS = 'Texas', SALARY=20000;
现在,COMPANY表将有以下记录 :
id | name | age | address | salary ----+-------+-----+---------+-------- 1 | Paul | 32 | Texas | 20000 2 | Allen | 25 | Texas | 20000 4 | Mark | 25 | Texas | 20000 5 | David | 27 | Texas | 20000 6 | Kim | 22 | Texas | 20000 7 | James | 24 | Texas | 20000 3 | Teddy | 23 | Texas | 20000 (7 rows)