如何优化这个代码可以为O(n)的分配值@TollPrice运行:如何优化这个SQL查询
IF (EXISTS (SELECT TollPrice
FROM Car_TaxInfo
WHERE (car_subgrp_id = @Kind) AND (Sal = @Sal)))
BEGIN
SELECT @TollPrice = TollPrice
FROM Car_TaxInfo
WHERE (car_subgrp_id = @Kind) AND (Sal = @Sal)
SET @IsExistToll = 1
END
ELSE
BEGIN
SET @IsExistToll = 0
END
删除if存在,只需选择该值并在其后面检查@@ rowcount。另外,检查是否有正确的索引 –
@JamesZ谢谢;) –