作业帮select * from book where 1=1这个条件语句中1=1是什么意思?
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select * from book where 1=1这个条件语句中1=1是什么意思?
select * from book where 1=1
这个条件语句中1=1是什么意思?
select * from book where 1=1这个条件语句中1=1是什么意思?
没什么意思,这个是做查询是用的,1=1是为了避免其他查询为空时,这条查询语句报错.
如果查询语句为空则显示为select * from book where
这条语句就会报错了,加上1=1,有查询条件,语句不会报错.
select * from book limit ,
select * from book where 1=1这个条件语句中1=1是什么意思?
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