HenryWang

摘要： 1，比较NULL值SELECT OrderDate,SalesOrderNumber,CustomerID,Subtotal FROM Sales.SalesOrderHeader WHERE CurrencyRateID is nullor .....from Sales.SalesOrderHeader WHERE CurrencyRateID=null选择不是NULL值的行： select OrderDate,SalesOrderNumber,CustomerID,Subtotal,TaxAmt from Sales.SalesORderHeader WHERE NOT Currency 阅读全文