是的,在一般情况下,检测是否有重复,
Select [ColumnList you want to be unique]
From Table
Group By [SameColumn List]
Having Count(*) > 1
在您的具体情况
Select person_id, company_id, financial_year
From Table
Group By person_id, company_id, financial_year
Having Count(*) > 1
,或者为你的子问题(1)是否每个为person_id每COMPANY_ID每financial_year在此表中最多出现一次
Select company_id, financial_year
From Table
Group By company_id, financial_year
Having Count(Person_Id) > 1
和(2):(当(1)是假的,这为person_id的和的company_id的和financial_year的共同出现一次
Select person_id, company_id, financial_year
From Table T
Where Not Exists
(Select * From Table
Where company_id = T.company_id
And financial_year = T.financial_year
Having Count(Person_Id) > 1)
Group By person_id, company_id, financial_year
Having Count(*) > 1
有条款应该在群组之后。 – jackrabbit 2009-01-02 18:42:14