SQL subquery return more that 1 value

Question

Hi I am trying to execute a query to get row between certain number , Like i am trying to get rows between 10-20. so i am using subquery so that i can use row_number() function

The query fails with the error:

SQL subquery return more that 1 value

So I need to figure a way out because I need to get more that 1 resulset out of the query

PROCEDURE dbo.Search

    (
    @search_text varchar(max), 
    @search_category varchar(max),
    @page int,
    @COUNT INT OUTPUT
    )

AS

     SET NOCOUNT ON
     DECLARE @Lower_limit int = (@page-1)*10;
     DECLARE @Upper_limit int = (@page * 10) + 1;
    -- SET @COUNT =0
     IF @search_category='deal'
     BEGIN
        SET @COUNT = (SELECT COUNT(*) FROM dealData WHERE dealInfo LIKE  '%' + @search_text + '%' OR dealName LIKE '%' + @search_text + '%' OR dealDescription LIKE  '%' + @search_text + '%' GROUP BY dealId);
        SELECT x.dealId , x.ROW 
        FROM
        ( SELECT dealId,ROW_NUMBER() OVER(ORDER BY dealId) as ROW from dealData WHERE dealInfo LIKE  '%' + @search_text + '%' OR dealName LIKE '%' + @search_text + '%' OR dealDescription LIKE  '%' + @search_text + '%'  GROUP BY dealId)x   
        WHERE x.ROW < @Upper_limit AND x.ROW > @Lower_limit
     END

This is the full procedure and when i try to call it from the following code I get exception at _command.ExecuteReader(); Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

 _query = "Search";
                _command = new SqlCommand(_query, _connection);
                _command.CommandType = CommandType.StoredProcedure;
                _command.Parameters.AddWithValue("@search_text", search_text);
                _command.Parameters.AddWithValue("@search_category", search_category);
                _command.Parameters.AddWithValue("@page", page);
                var returnParameter = _command.Parameters.Add("@COUNT", SqlDbType.Int);
                returnParameter.Direction = ParameterDirection.Output;
                _reader = _command.ExecuteReader();
                while (_reader.Read())
                {
                    search_result index = new search_result();
                    index.category_id = this._categoryIdFromName(search_category);
                    index.post_id = _reader.GetValue(0).ToString();
                    _searchList.Add(index);
                }

Answer 1

The problem is this part of your sp:

SET @COUNT = (  SELECT COUNT(*) FROM dealData 
                WHERE dealInfo LIKE  '%' + @search_text + '%' 
                OR dealName LIKE '%' + @search_text + '%' 
                OR dealDescription LIKE  '%' + @search_text + '%' 
                GROUP BY dealId)

Specifically, the GROUP BY dealId part. If you have multiple dealId on that table, then you are going to get multiple rows as a result. Obviously, you can't assign that on a scalar variable. Either @Count will need to be declared as a table variable (which will change the logic of the rest of your sp), or you get rid of the GROUP BY dealId , and verify that it gives you your desired results.

Answer 2

I have to agree with @Lamak, and am only posting an answer so that repetition may inflict knowledge. If you re-write your assignment the following way, your problem will go away:

SELECT @COUNT = COUNT(*) 
  FROM dbo.dealData 
  WHERE dealInfo        LIKE '%' + @search_text + '%' 
     OR dealName        LIKE '%' + @search_text + '%' 
     OR dealDescription LIKE '%' + @search_text + '%' 
  /* GROUP BY dealId */ -- there is NO REASON for this grouping if you want total count!
;

Answer 3

Aside from what everyone else has stated about the subquery that populates the variable returning multiple rows, there may be a more efficient means to get at what you seek (which I'm assuming is paging). This assumes that GroupId is the Primary Key of the DealData table as stated in comments:

Declare @Results Table
    (
    DealId ... not null Primary Key
    , RowNumAsc int not null
    , TotalCount int not null
    );

With NumberedData As
        (
        Select DealId
            , Row_Number() Over ( Order By GroupId ) As RowNumAsc
            , Row_Number() Over ( Order By GroupId Desc ) As RowNumDesc
        From DealData
        Where dealInfo LIKE  '%' + @search_text + '%' 
            Or dealName LIKE '%' + @search_text + '%' 
            Or dealDescription LIKE  '%' + @search_text + '%'  
        )
Insert @Results( DealId, RowNumAsc, TotalCount )
Select DealId, RowNumAsc
    , Min( RowNumAsc + RowNumDesc - 1 ) As Count
From NumberedData
Where RowNumAsc < @UpperLimit
    And RowNumAsc >= @LowerLimit
Group By DealId 

Set @Count = ( Select TOP 1 TotalCount From @Results );
Select DealId, RowNumAsc
From @Results