存储过程，如果不存在任何记录

Question

I got this stored procedure,

Create procedure [dbo].[Craping_GetFruitCrapedOrNot]
(
    @FruitID int,
    @CrateID int,
    @FruitName varchar(100)
)
AS
    SELECT Craping.Craped
    FROM Fruits 
    INNER JOIN Craping ON Fruits.ID = Craping.FruitID
    WHERE     
        (Fruits.FruitTable = @FruitName) 
        AND (Craping.FruitID = @FruitID) 
        AND (Craping.CrateID = @CrateID)
GO

Now I want to check if Fruits table has the fruit with provided fruit name, if there isn't any fruit then return true.

If Fruits and Craping table's inner join got no record for a FruitID , CrateID and FruitName then return true not false.

What we are trying to do is to only get false when a fruit is craped and logged to table.

Answer 1

You can use IF EXISTS to determine the presence of the row, and then use CASE WHEN to project this as the result you need, eg

Create procedure [dbo].[Craping_GetFruitCrapedOrNot]
(
    @FruitID int,
    @CrateID int,
    @FruitName varchar(100)
)
AS
  SELECT CASE WHEN EXISTS
  (
     SELECT     1
     FROM         Fruits 
          INNER JOIN Craping 
          ON Fruits.ID = Craping.FruitID
     WHERE     
         (Fruits.FruitTable = @FruitName) 
         AND (Craping.FruitID = @FruitID) 
         AND (Craping.CrateID = @CrateID)
  ) 
  THEN 'False'
  ELSE 'True'
  END AS FruitNotCraped
GO   

Do you mind if I ask a question: What is a Craped Fruit? ;)

SqlFiddle here