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SQL点滴之with语句和子查询的性能比较
发布时间：2025-11-04 23:34:48 来源：创站工坊 作者：域名
复制/*with查询*/ declare @withquery varchar(5000) declare @execcount int=0 set @withquery=with TheseEmployees as( select empid from hr.employees where country=NUSA),点滴 CharacteristicFunctions as( select custid, casewhen custid in (select custid from sales.orders as o where o.empid=e.empid) then 1 else 0 endas charfun from sales.customers as c crossjoin TheseEmployees as e) select custid from CharacteristicFunctions groupby custid havingmin(charfun)=1 orderby custid while @execcount<10 begin exec (@withquery); set @execcount=@execcount+1 end /*子查询*/ declare @subquery varchar(5000) declare @execcount int=0 set @subquery=select custid from Sales.Orders where empid in (select empid from HR.Employees where country = NUSA) groupby custid havingcount(distinct empid)=(selectcount(*) from HR.Employees where country = NUSA); while @execcount<10 begin exec (@subquery); set @execcount=@execcount+1 end 1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.
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