1、要删除多条记录怎么办？in 表示一个集合。
（1）Delete T_Employee where FId in (21,22)
（2）SELECT FAge,FNumber,FName FROM T_Employee WHERE FAge IN (23,25,28)
2、范围值：
（1）SELECT * FROM T_Employee WHERE FAGE>=23 AND FAGE <=27
（2）SELECT * FROM T_Employee WHERE FAGE BETWEEN 23 AND 27
3、例：
select null+1select 'abc'+'123'select ''+'123'select null+'123'select * from T_Employee
where FName<>nullselect * from T_Employee
where FName is null;select * from T_Employee
where FName is not null;select * from T_Employee
where FAge=23 or FAge=25 or FAge=28select * from T_Employee
where FAge in (23,25,28)select * from T_Employee
where FAge>20 and FAge<30select * from T_Employee
where FAge between 20 and 30