SqlServer_临时表查询和内联子查询的使用；

<span style="font-size:18px;">功能：查询订单表中每个顾客第一次下订单的订单号和时间；(1)、临时表使用USE AdventureWorks2008GOSELECT soh.CustomerID, MIN(soh.OrderDate) AS OrderDateINTO #MinOrderDatesFROM Sales.SalesOrderHeader sohGROUP BY soh.CustomerID;SELECT soh.CustomerID, soh.SalesOrderID, soh.OrderDateFROM Sales.SalesOrderHeader sohJOIN #MinOrderDates tON soh.CustomerID = t.CustomerIDAND soh.OrderDate = t.OrderDateGROUP BY soh.CustomerIDDROP TABLE #MinOrderDates(2)、内联子查询SELECT soh1.CustomerID, soh1.SalesOrderID, soh1.OrderDateFROM Sales.SalesOrderHeader soh1WHERE soh1.OrderDate  = (SELECT Min(soh2.OrderDate)FROM Sales.SalesOrderHeader soh2WHERE soh2.CustomerID = soh1.customerID)ORDER BY CustomerID;</span>