用于SQL的VLOOKUP

时间:2016-10-06 14:25:37

标签: sql sql-server

我有两列数据需要相互比较:

第1栏:

 People
 Trust
 Corporate

第2栏:

 People    
 People     
 People    
 Company
 Corporate      
 Corporate
 Corporate
 Company
 Trust
 Trust 

COLUMN 1比COLUMN 2短,但是是站立数据与COLUMN 2进行比较。我想找到COLUMN 2中不属于COLUMN 1的值。

这样的结果是我正在寻找的:

 People      TRUE
 People      TRUE
 People      TRUE
 Company     FALSE
 Corporate   TRUE 
 Corporate   TRUE 
 Corporate   TRUE 
 Company     FALSE
 Trust       TRUE
 Trust       TRUE

这些列位于两个不同的表中。我正在使用SQL。 有什么建议吗?

3 个答案:

答案 0 :(得分:2)

使用CASE WHEN EXISTS

select Column2, 
       case
         when exists (select Column1 from Table1 T1 where T1.Column1 = Column2)
           then 'TRUE'
         else 'FALSE'
from Table2

答案 1 :(得分:2)

其他答案都是正确的,但我总是发现使用LEFT JOIN更快: (我不知道这是不是我的看法,或者它是否真的更具表现力)

SELECT 
  T2.COLUMN, 
  CASE WHEN T1.COLUMN IS NULL THEN 'FALSE' ELSE 'TRUE' END EXISTENT
FROM TABLE_2 T2
LEFT OUTER JOIN TABLE_1 T1
ON T2.COLUMN = T1.COLUMN

答案 2 :(得分:0)

答案都是正确的,但如果您想要实际的真或假而不是字符串,您可以转换为位字段:

declare @temp1 table (column1 varchar(50)) 
declare @temp2 table (column1 varchar(50))

insert into @temp1 (column1) values ('people')
insert into @temp1 (column1) values ('trust')
insert into @temp1 (column1) values ('corporate')

insert into @temp2 (column1) values ('People')    
insert into @temp2 (column1) values ('People')     
insert into @temp2 (column1) values ('People')    
insert into @temp2 (column1) values ('Company')
insert into @temp2 (column1) values ('Corporate')      
insert into @temp2 (column1) values ('Corporate')
insert into @temp2 (column1) values ('Corporate')
insert into @temp2 (column1) values ('Company')
insert into @temp2 (column1) values ('Trust')
insert into @temp2 (column1) values ('Trust')

select t2.column1, convert(bit, case when t1.column1 is null then 0 else 1 end)
from   @temp2 t2
  left join @temp1 t1 on t2.column1 = t1.column1