ns of the left and right-hand SEL

【文件属性】：
文件名称：ns of the left and right-hand SEL
文件大小：520KB
文件格式：B
更新时间：2014-08-18 12:21:15
sdfewe e results of compound SELECT operators, NULL values are considered equal to other NULL values and distinct from all non-NULL values. The collation sequence used to compare two text values is determined as if the columns of the left and right-hand SELECT statements were the left and right-hand operands of the equals (=) operator, except that greater precedence is not assigned to a collation sequence specified with the postfix COLLATE operator. No affinity transformation