SQL子查詢返回的值超過1

Question

嗨，我正在嘗試執行查詢以獲取特定數字之間的行，就像我正在嘗試獲取10-20之間的行。 所以我正在使用子查詢，以便我可以使用row_number()函數

查詢失敗，並顯示以下錯誤：

SQL子查詢返回的值超過1

所以我需要找出一個出路，因為我需要從查詢中獲得1個以上的結果

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

這是完整的過程，當我嘗試從以下代碼調用它時，在_command.ExecuteReader（）;中出現異常。 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

問題是您的sp的這一部分：

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

具體來說，是GROUP BY dealId部分。 如果該表上有多個dealId ，那么結果將是獲得多行。 顯然，您不能將其分配給標量變量。 需要將@Count聲明為表變量（這將更改sp其余部分的邏輯），或者您擺脫了GROUP BY dealId ，並驗證它是否可以提供所需的結果。

Answer 2

我必須同意@Lamak，並且僅發布答案，以便重復可能會影響知識。 如果您通過以下方式重新編寫作業，則問題將消失：

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

除了關於填充返回多行變量的子查詢的其他人所說的以外，可能還有一種更有效的方法來獲得您想要的內容（我假設是分頁的）。 如注釋中所述，這假定GroupId是DealData表的主鍵：

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