如果我们想删除成绩不及格的学生记录,可以使用NOT IN条件来排除成绩大于等于60分的学生。 以下是使用NOT IN条件的DELETE语句示例: DELETEFROMstudentsWHEREscoreNOTIN(SELECTscoreFROMstudentsWHEREscore>=60); 1. 2. 在这个示例中,我们首先从students表中选择成绩大于等于60分的学生,然后使用NOT IN条件删除不符合条件的...
MySQL比较恶心的一个delete in操作 MySQL中 deletefromtableAwhereidnotin(1,2,3); 1. 是没有问题的 deletefromtableAwhereidnotin(selectidfromtableB) 1. 也是没有问题的 但是 deletefromtableAwhereidnotin(selectidfromtableA) 1. 就TMD有问题了。 解决办法是给里面的子查询建立表别名 deletefromtableA(...
delete from activity_student where student_id not in (select sid from students) 解决办法是通过临时表创建索引,用空间换时间避免频繁读取原表信息。 delete from activity_student where student_id not in (select * from (select sid from students) tmp) 改成上面的 sql 语句后,40 秒结束战斗! 网上说 ...
mysql delete not in 想要执行: DELETEFROMtb_tableAWHEREidIN(SELECTa.idFROMtb_tableA aWHEREa.idNOTIN(SELECTa_idFROMtb_tableB ) ); 是无法正确执行的。 解决方案:创建临时表,作为中间表;用完再删去。 CREATETABLEtmpASSELECTt.idFROM(SELECTa.idFROMtb_tableA aWHEREa.idNOTIN(SELECTa_idFROMtb_tableB...
我试了select * from stu_score where (stu_id,course_id,score) not in (select stu_id,course_id,max(score) as score from stu_score group by stu_id,course_id) 这样的语句,其中只是把delete替换成了select * ,执行起来就是秒出,并无delete时的阻滞。
DELETE FROM CIDZ WHERE EXISTS (SELECT 1 FROM CIDZ A WHERE A.ID > CIDZ.ID AND A.地址 = CIDZ.地址)你运行一下试试。因为NOT IN是一个检索，要先运行IN里面的语句，这样相当于多了一个全表的检索操作，先把范围选出来，所以当你的表数据非常大的时候，速度会非常慢。可是EXISTS语句就不...
二、词性和意思不同：delete 动词，意思是删除、删去、划掉、擦去、去掉 delegation 名词，意思是代表团、委托、委派 三、用法不同：delete 用作及物动词 (vt.)1、Delete his name from the list.把他的名字从名单上删去。2、The attack is to wipe out data, to delete flies, or to format...
For more information, see FROM (Transact-SQL).WHERE Specifies the conditions used to limit the number of rows that are deleted. If a WHERE clause is not supplied, DELETE removes all the rows from the table.There are two forms of delete operations based on what is specified in the WHERE ...
2、delete from删除；从…上删掉 3、delete keyn. [计]删除字符键 例句：1、Dreams organize the events of the day into folders and delete what is not needed.在梦中，一天的事情被分门别类地整理好，而不必要的则会被删除。2、We will be pleased to delete the charge from the original...
Example 3: Delete_From Notexists Join You can use the notexists join keyword pair in a delete_from statement. The delete_from statements in the following X++ code example are efficient. The notexists join clause enables the delete_from statement to delete a specific set of rows. In this ...