目录
前言
在业务开展中,会遇到类似需求。
需求1:UPDATE表TEST_TB01中的记录;满足条件:这些记录不在TEST_TB02中。
需求2:UPDATE表TEST_TB01中的记录;满足条件:这些记录在TEST_TB02中。
在SQL语句中EXISTS的用法,能够比较简洁的去解决这类需求。
一、建表
1.在MySQL数据库建表语句
CREATE TABLE TEST_TB01
(
sensor_id BIGINT,
part_id BIGINT,
flag VARCHAR(64)
)
COMMENT '数据表一';
CREATE TABLE TEST_TB02
(
sensor_id BIGINT,
part_id BIGINT,
flag VARCHAR(64)
)
COMMENT '数据表二';
CREATE TABLE TEST_TB03
(
sensor_id BIGINT,
part_id BIGINT,
flag VARCHAR(64)
)
COMMENT '数据表三';
2.在ORACLE数据库建表语句
CREATE TABLE TEST_TB01
(
sensor_id NUMBER(16),
part_id NUMBER(16),
flag VARCHAR(64)
);
CREATE TABLE TEST_TB02
(
sensor_id NUMBER(16),
part_id NUMBER(16),
flag VARCHAR(64)
);
二、在SELECT语句中使用EXISTS
在SELECT的SQL语句中使用EXISTS。
在TEST_TB01插入数据:
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2101,8811,'厦门');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2102,8812,'泉州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2103,8813,'福州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2104,8814,'漳州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2105,8815,'杭州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2106,8816,'上海');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2107,8817,'北京');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2108,8818,'深圳');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2109,8819,'中国');
在TEST_TB02插入数据:
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2101,8811,'厦门');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2102,8812,'泉州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2103,8813,'福州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2104,8814,'漳州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2109,8819,'中国');
在TEST_TB03插入数据:
INSERT INTO TEST_TB03 (sensor_id,part_id,flag) VALUES(2106,8816,'上海');
INSERT INTO TEST_TB03 (sensor_id,part_id,flag) VALUES(2107,8817,'北京');
INSERT INTO TEST_TB03 (sensor_id,part_id,flag) VALUES(2109,8819,'中国');
查看TEST_TB01数据:
查看TEST_TB02数据:
查看TEST_TB03数据:
1.在SQL中使用EXISTS
需求:从TEST_TB01中查询出在TEST_TB02中存在的记录,关联条件是两个表的sensor_id相等。
SQL语句:
SELECT
aa.sensor_id,aa.part_id,aa.flag
FROM
TEST_TB01 aa
WHERE EXISTS
(SELECT 1 FROM
TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id);
执行结果:
2.在SQL中使用NOT EXISTS
需求:从TEST_TB01中查询出在TEST_TB02中不存在的记录,关联条件是两个表的sensor_id相等。
SQL语句:
SELECT
aa.sensor_id,aa.part_id,aa.flag
FROM
TEST_TB01 aa
WHERE NOT EXISTS
(SELECT 1 FROM
TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id);
执行结果:
3.在SQL中使用多个NOT EXISTS
需求:从TEST_TB01中查询出在TEST_TB02和TEST_TB03中都不存在的记录,关联条件是表的sensor_id相等。
SQL语句:
SELECT
aa.sensor_id,aa.part_id,aa.flag
FROM
TEST_TB01 aa
WHERE NOT EXISTS
(SELECT 1 FROM
TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id)
AND NOT EXISTS
(SELECT 1 FROM
TEST_TB03 cc
WHERE aa.sensor_id = cc.sensor_id);
执行结果:
4.在SQL中使用多个EXISTS
需求:从TEST_TB01中查询出在TEST_TB02和TEST_TB03中都存在的记录,关联条件是表的sensor_id相等。
SQL语句:
SELECT
aa.sensor_id,aa.part_id,aa.flag
FROM
TEST_TB01 aa
WHERE EXISTS
(SELECT 1 FROM
TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id)
AND EXISTS
(SELECT 1 FROM
TEST_TB03 cc
WHERE aa.sensor_id = cc.sensor_id);
执行结果:
5.在SQL中使用NOT EXISTS和EXISTS
需求:从TEST_TB01中查询出在TEST_TB02存在但是TEST_TB03中不存在的记录,关联条件是表的sensor_id相等。
SQL语句:
SELECT
aa.sensor_id,aa.part_id,aa.flag
FROM
TEST_TB01 aa
WHERE EXISTS
(SELECT 1 FROM
TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id)
AND NOT EXISTS
(SELECT 1 FROM
TEST_TB03 cc
WHERE aa.sensor_id = cc.sensor_id);
执行结果:
三、在DELETE语句中使用EXISTS
在DELETE的SQL语句中使用EXISTS和NOT EXISTS。
在TEST_TB01插入数据:
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2101,8811,'厦门');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2102,8812,'泉州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2103,8813,'福州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2104,8814,'漳州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2105,8815,'杭州');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2106,8816,'上海');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2107,8817,'北京');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2108,8818,'深圳');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2109,8819,'中国');
在TEST_TB02插入数据:
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2101,8811,'厦门');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2102,8812,'泉州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2103,8813,'福州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2104,8814,'漳州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2109,8819,'中国');
1.在MySQL中使用
需求:从TEST_TB01中删除在TEST_TB02中存在的记录,关联条件是两个表的sensor_id相等。
注意:本例使用MySQL版本:MySQL 5.7.33。
SQL语句:
DELETE FROM
TEST_TB01 aa
WHERE EXISTS
(SELECT 1 FROM
TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id);
执行结果:
结论:在MySQL中是不支持在DELETE的SQL语句中使用EXISTS和NOT EXISTS这种句法。(本例版本:MySQL 5.7.33)。
解决此需求:
SQL语句:
DELETE
aa
FROM
TEST_TB01 aa
INNER JOIN TEST_TB02 bb
ON aa.sensor_id = bb.sensor_id;
注意:在SQL中DELETE后面紧跟着的是需求中需要删除的表名的别名。
如果不使用别名会报错:
2.在Oracle中使用
需求:从TEST_TB01中删除在TEST_TB02中存在的记录,关联条件是两个表的sensor_id相等。
SQL语句:
DELETE FROM
TEST_TB01 aa
WHERE EXISTS
(SELECT 1 FROM
TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id);
执行结果:
执行前TEST_TB01:
执行前TEST_TB02:
执行后TEST_TB01:
四、在UPDATE语句中使用EXISTS
在UPDATE的SQL语句中使用EXISTS。
在TEST_TB01插入数据:
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2101,8811,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2102,8812,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2103,8813,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2104,8814,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2105,8815,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2106,8816,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2107,8817,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2108,8818,'城市');
INSERT INTO TEST_TB01 (sensor_id,part_id,flag) VALUES(2109,8819,'城市');
在TEST_TB02插入数据:
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2101,8811,'厦门');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2102,8812,'泉州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2103,8813,'福州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2104,8814,'漳州');
INSERT INTO TEST_TB02 (sensor_id,part_id,flag) VALUES(2109,8819,'中国');
1.在MySQL中使用
需求:在TEST_TB01中更新,在TEST_TB02中存在的记录,关联条件是两个表的sensor_id相等。
注意:本例使用MySQL版本:MySQL 5.7.33。
SQL语句:
UPDATE TEST_TB01 aa
SET (aa.part_id, aa.flag) =
(SELECT bb.part_id, bb.flag
FROM TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id)
WHERE EXISTS
(SELECT 1 FROM TEST_TB02 cc
WHERE aa.sensor_id = cc.sensor_id);
执行结果:
结论:在MySQL中是不支持在UPDATE的SQL语句中使用EXISTS和NOT EXISTS这种句法。(本例版本:MySQL 5.7.33)。
解决此需求:
SQL语句:
UPDATE TEST_TB01 aa ,TEST_TB02 bb
SET
aa.part_id=bb.part_id,
aa.flag=bb.flag
WHERE aa.sensor_id = bb.sensor_id;
执行结果:
执行前TEST_TB01:
执行前TEST_TB02:
执行后TEST_TB01:
2.在Oracle中使用
需求:在TEST_TB01中更新,在TEST_TB02中存在的记录,关联条件是两个表的sensor_id相等。
SQL语句:
UPDATE TEST_TB01 aa
SET (aa.part_id, aa.flag) =
(SELECT bb.part_id, bb.flag
FROM TEST_TB02 bb
WHERE aa.sensor_id = bb.sensor_id)
WHERE EXISTS
(SELECT 1 FROM TEST_TB02 cc
WHERE aa.sensor_id = cc.sensor_id);
执行结果:
执行前TEST_TB01:
执行前TEST_TB02:
执行后TEST_TB01:
以上,感谢。
总结
到此这篇关于SQL语句中EXISTS用法的文章就介绍到这了,更多相关SQL语句EXISTS用法内容请搜索三水点靠木以前的文章或继续浏览下面的相关文章希望大家以后多多支持三水点靠木!
SQL语句中EXISTS的详细用法大全
- Author -
zhangbeizhen18- Original Sources -
声明:登载此文出于传递更多信息之目的,并不意味着赞同其观点或证实其描述。
Tags in this post...
Reply on: @reply_date@
@reply_contents@