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?
? 求差集
? select distinct abc from A where exists (SELECT valueFROM A uc WHERE? id='1')
?? ?
? except
?? ?select distinct abc from A where CityId in (SELECT value FROM B uc WHERE? id='1')
?
?
?
--按分类重新构建表结构
?with A1 as
(
?? ?select Aid,A1name from A where type='A1'
),
A2 as
(
?? ?select A2id,A2name from A where type='A2'
),
A3 as
(
?? ?select A3id,A3name from A where type='A3'
),
A4 as
(
select A4id,A4name from A where type='A4'
)
select A1.A1id,A2.A2name,A3.A3id,A4.A4name
into A1A2A3A4
from A1 A
?left join A2 B on? condition1
left join A3 C on? condition2
left join A4 D on condition3
--创建非聚合索引
create NONCLUSTERED INDEX indexName on A1A2A3A4(A1name,A2name,A3name);
?
?
exists使用
?
?
?
子查询方法
例：select top 3 * from (select top 5 id,vNo from vProduction where 1=1 order by id desc) as tab 将查询另取为表名
?
?
REPLACE(STR,'-','') 替换字符串中的一些字符
CONVERT(VARCHAR,GETDATE(),112) 按112格式yymmdd将日期转为字符串
cast(123 as nvarchar) 将数字转换为字符串
（编辑：李大同）
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