PostgreSQL DELETE 查询用于从表中删除现有记录,您可以将WHERE子句与DELETE查询一起使用,以删除选定的行,否则,所有记录将被删除。
带WHERE子句的DELETE查询的基本语法如下-
DELETE FROM table_name WHERE [condition];
您可以使用AND或OR运算符组合N个条件。
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考虑表 COMPANY ,其记录如下:
# select * from COMPANY; id | name | age | address | salary ----+-------+-----+-----------+-------- 1 | Paul | 32 | California| 20000 2 | Learnfk | 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,它将删除ID为2的客户-
testdb=# DELETE FROM COMPANY WHERE ID = 2;
现在,COMPANY表将具有以下记录-
id | name | age | address | salary ----+-------+-----+-------------+-------- 1 | Paul | 32 | California | 20000 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 (6 rows)
如果要删除COMPANY表中的所有记录,则无需对WHERE子句使用DELETE查询,如下所示-
testdb=# DELETE FROM COMPANY;
现在,COMPANY表没有任何记录,因为所有记录已被DELETE语句删除。
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