SQL必知必會過濾資料

where子句：

select [vend_name],[vend_address] from [test].[dbo].[vendors] where [vend_name] = 'hanma'

注：當有order by 和 where 時，where 在order by 前面

where子句操作符：

單個值檢查：

select [vend_name],[vend_address],[vend_zip] from [test].[dbo].[vendors] where [vend_zip] < 11111111

不匹配檢查：

select [vend_name],[vend_address],[vend_zip] from [test].[dbo].[vendors] where [vend_name] != 'defu'

範圍值檢查：

select [vend_name],[vend_address],[vend_zip] from [test].[dbo].[vendors] where [vend_name] between 'hanma' and 'zhongshihua'

空值檢查：null 它與空格，或者空字串不同。

select [vend_name],[vend_address],[vend_zip] from [test].[dbo].[vendors] where [vend_city] is null

and操作符：

select [vend_name],[vend_address],[vend_zip] from [test].[dbo].[vendors] where [vend_city] is not null and [vend_name] > 'defu'

or操作符：

select [vend_name],[vend_address],[vend_zip],[vend_city] from [test].[dbo].[vendors] where [vend_city] is null or [vend_name] <= 'defu'

注：子句在處理or操作符之前會優先處理and操作符

in操作符:是用來指定條件範圍的，範圍中的每乙個條件都可以匹配。

select [vend_name],[vend_address],[vend_zip],[vend_city]from [test].[dbo].[vendors] where [vend_city] in ('bolin','haidian『)

not操作符：

select [vend_name],[vend_address],[vend_zip],[vend_city] from [test].[dbo].[vendors] where not [vend_city] in ('bolin','haidian')

SQL必知必會 過濾資料