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MYSQL 当有两条重复数据时 保留一条

时间:2021-07-01 10:21:17 帮助过:2人阅读

delete from test  where id in (select id from (select  max(id) as id,count(text) as count from test group by text having count >1 order by count desc) as tab )

测试代码

 INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘22222‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘22222‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘22222‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘22222‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘22222‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘1111‘,‘33333‘);
 INSERT IGNORE INTO test_1(text,text2) values (‘22222‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘22222‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘22222‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘22222‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘22222‘,‘33333‘); INSERT IGNORE INTO test_1(text,text2) values (‘22222‘,‘33333‘);

 REPLACE  INTO test(text) values (‘1111‘)
delete from test
select * from test_1 where text=‘1111‘select * from test_1 where text=‘22222‘
while delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );
delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );delete from test_1  where id in (select id from (select  max(id) as id,count(text) as count from test_1 where text = ‘22222‘ group by text,text2 having count >1 order by count desc) as tab );


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MYSQL 当有两条重复数据时 保留一条

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