sql distinct

---沒有去除重復的記錄
select distinct ContractLaborEmployeeUidKey,ContractLaborEndDate from ContractLaborList order by ContractLaborEndDate desc



select  * from ContractLaborList order by ContractLaborEmployeeUidKey

---沒有去除重復的記錄
select * from ContractLaborList where ContractLaborEmployeeUidKey in (select distinct ContractLaborEmployeeUidKey from ContractLaborList)
order by ContractLaborEndDate desc

--去除ContractLaborEmployeeUidKey重復的記錄
select * from ContractLaborList where ContractLaborEndDate in( SELECT MAX(ContractLaborEndDate) AS ContractLaborEndDate FROM ContractLaborList GROUP BY ContractLaborEmployeeUidKey) --重复行只查询一条
order by ContractLaborEndDate desc

---去除ContractLaborEmployeeUidKey重復的記錄
select * from ContractLaborList e 
WHERE e.ContractLaborEndDate = (SELECT max(x.ContractLaborEndDate) FROM ContractLaborList x WHERE x.ContractLaborEmployeeUidKey = e.ContractLaborEmployeeUidKey);

SELECT * FROM View_ContractLaborList

--取出ContractLaborEmployeeUidKey重復的值
SELECT  * FROM ContractLaborList s2
WHERE 1 < (SELECT COUNT(*)  FROM ContractLaborList s1 WHERE s1.ContractLaborEmployeeUidKey = s2.ContractLaborEmployeeUidKey)