将 varchar 值转换为数据类型 int 时，SQL Select Case Conversion 失败

Question

With the help of case statement, I would like to get the result as "Non Revenue" in Geodept column where the value is 0

Simple case statement - (gives conversion error)

case when GeoDeptId = 0 then 'Non Revenue' else GeoDeptId end

So tried as below but getting value as 0 again

convert(int, case when IsNumeric(convert(int, rd.GeoDeptId ))= 0 then convert (varchar(14),'Non Revenue') else rd.GeoDeptId
end ),

So tried as below but getting value as 0 again

convert(int, case when IsNumeric(convert(int, rd.GeoDeptId ))= 0 then convert (varchar(14),'Non Revenue') else rd.GeoDeptId
end )

Answer 1

Cast the GeoDeptId to text:

CASE WHEN GeoDeptId = 0 THEN 'Non Revenue' ELSE CAST(GeoDeptId AS varchar(max)) END

The source of your error is that all branches of a CASE expression must have the same type. Since it is not possible for 'Non Revenue' to be cast to an integer, therefore we can convert the GeoDeptId to text.