<>和!=都是不等于
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%和_通配符
[] 和[^]
telcod like '13[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'
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and,or,not
先求not，然后and，最后or
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一次插入多行
insert into atable(....) select ...... from btable where ........
insert into students(.....)
select ..,..,.. union
select ..,..,.. union
select ...,...
将多行插入新表
select .... into btable from atable
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like，between,sum,avg,in,
