存储过程操作数类型冲突：日期与int不兼容

Question

This is my stored procedure

ALTER PROCEDURE [dbo].[sp_ListFirmJobFilter]
    (@Status as nvarchar(10),
     @CityID as nvarchar(10),
     @DataStart as date,
     @DataEnd as date,
     @FirmID as nvarchar(10)
)
AS
BEGIN
    DECLARE @Sql NVARCHAR(MAX) 
    SET @Sql = N'SELECT * FROM Jobs WHERE 1=1'

    IF @Status IS NOT NULL
    BEGIN
        SET @Sql += ' AND Status = '+@Status+''
    END

    IF @CityID IS NOT NULL
    BEGIN
        SET @Sql += ' AND CityID = '+@CityID+''
    END

    IF @FirmID IS NOT NULL
    BEGIN
        SET @Sql += ' AND FirmID = '+@FirmID+' '
    END

    IF @DataStart IS NOT NULL
    BEGIN
        SET @Sql += ' AND (InsertedDate >= ' + CONVERT(VARCHAR(50), @DataStart)
        SET @Sql += ' AND InsertedDate <= ' + CONVERT(VARCHAR(50), @DataEnd)
        SET @Sql += ')'
    END 

    PRINT(@Sql)
    EXEC(@Sql)
END

The command completed successfully.

But when I execute that stored procedure with that parameter

DECLARE @return_value int

EXEC @return_value = [dbo].[sp_ListFirmJobFilter]
                        @Status = NULL,
                        @CityID = null,
                        @DataStart = N'2016-06-26',
                        @DataEnd = N'2016-06-28',
                        @FirmID = 4

SELECT  'Return Value' = @return_value
GO

I get an error:

Operand type clash: date is incompatible with int

I look for executed SQL command (Print SQL string). This is executed command:

SELECT * 
FROM Jobs 
WHERE 1=1 
  AND FirmID = 4  
  AND (InsertedDate >= 2016-06-26 AND InsertedDate <= 2016-06-28)

When I execute that it give same error. I changed it to:

SELECT * 
FROM Jobs 
WHERE 1=1 
  AND FirmID = 4  
  AND (InsertedDate >= '2016-06-26' AND InsertedDate <= '2016-06-28')

this worked.

What should I do? InsertedDate type is date

Answer 1

Wrap dates in single quotes

SET @Sql += ' AND (InsertedDate >= ''' + CONVERT(VARCHAR(50), @DataStart) +''''
SET @Sql += ' AND InsertedDate <= ''' + CONVERT(VARCHAR(50), @DataEnd) +''''
SET @Sql += ')'

Answer 2

As mentioned by Squirrel, and you noticed it yourself as well, dates have to be enclosed in single quotes.

Personally I like to use QUOTENAME for this:

SET @Sql += ' AND InsertedDate <= ' + QUOTENAME(CONVERT(VARCHAR(50), @DataEnd), '''')

Answer 3

您需要将日期字符串括在单引号中

SET @Sql += ' AND (InsertedDate >= ==' + CONVERT(VARCHAR(50), @DataStart) + ''''