删除时如何查看查询影响的行数

启动事务,删除后回滚;

在psql中:

test1=> begin;
BEGIN
test1=> delete from test1 where test1_id = 1;
DELETE 2
test1=> rollback;
ROLLBACK

在pgAdmin中(在“输出窗格”的“历史记录”选项卡中):

-- Executing query:
begin;
Query returned successfully with no result in 16 ms.

-- Executing query:
delete from test1 where test1_id = 1;
Query returned successfully: 2 rows affected, 16 ms execution time.

-- Executing query:
rollback;
Query returned successfully with no result in 16 ms.

我不知道如何自动做到这一点,但你总是可以做一个选择,然后删除。

SELECT COUNT(*) FROM foo WHERE delete_me=true;

DELETE FROM foo WHERE delete_me=true;

DELETE 通过 SELECT COUNT(*) .

程序 之后 执行DELETE),许多编程语言为此提供了一个构造。例如,在PHP中 pg_affected_rows 在.NET中,它是 ExecuteNonQuery .

使用 RETURNING

DELETE FROM test1 WHERE test1_id = 1 RETURNING id;

从8.2版起,这一功能开始工作