Statements

EXCEPT
從左查詢傳回右查詢所未傳回的任何值

INTERSECT
傳回左右兩側都有的任何值



SELECT name FROM sys.databases;
{master,model,msdb,YKMDB,YK,YKTEST}

SELECT DISTINCT database_name database_name FROM msdb.dbo.backupset;
{VBMDB,Portal,SAP,YKMDB,YK}

== example ==
SELECT name databases FROM sys.databases WHERE name like 'm%' or name like 'Y%'
EXCEPT
SELECT DISTINCT database_name database_name FROM msdb.dbo.backupset;
==>> {master,model,msdb,YKTEST}

SELECT name databases FROM sys.databases WHERE name like 'm%' or name like 'Y%'
INTERSECT
SELECT DISTINCT database_name database_name FROM msdb.dbo.backupset;
==>> {YKMDB,YK}