我如何改进以下代码只使用一次“选择”？

IF EXISTS (SELECT [NUMBER] FROM [TABLE] WHERE [ID_RECORD] = @id_record
BEGIN
   DECLARE @tmp_variable
   SELECT @tmp_variable = [NUMBER] FROM [TABLE] WHERE [ID_RECORD] = @id_record

   SET @other_variable = @tmp_variable
END
ELSE
BEGIN
   SET @other_variable = 0
END

解决方法

试试这个 ：

DECLARE @tmp_variable INT
 SET @tmp_variable = ISNULL(( SELECT    [NUMBER]
                              FROM      [TABLE]
                              WHERE     [ID_RECORD] = @id_record
                             ),0)