SQLServer数据库Isnull()CAST()函数实例讲解

SELECT isnull(Sum(CAST(DAY0 AS DECIMAL(8,2)) ),0) as DAYSALES from SMASTOREFORECASTINFO

Isnull(): Sum(CAST(DAY0 AS DECIMAL(8,2)) )为NULL 时候 会把0赋值给DAYSALES

CAST():CAST(DAY0 AS DECIMAL(8,2)) 将每天的DAY0 值最多8位储存，2位小数