('1003' , NULL , '2002-05-20' , '男');
('1004' , '张三' , '2000-09-06' , '男');
('1005' , '李四' , '2001-12-01' , '女');
('1006' , NULL , '2001-12-02' , '女');
修改name字段为NULL的记录,是男生时设置name='男生姓名',是女生时设置name='女生姓名',如下SQL正确的是()?
update student_table set name = ( case when sex = '男' then '男生姓名' when sex = '女' then '女生姓名' end) if name is null ;
update student_table when name is null set name = ( case when sex = '男' then '男生姓名' when sex = '女' then '女生姓名')
update student_table set name = ( when sex = '男' then '男生姓名' when sex = '女' then '女生姓名') where name is null ;
update student_table set name = ( case when sex = '男' then '男生姓名' when sex = '女' then '女生姓名' end) where name is null ;