sql-server - 在sql server中进行排序时如何处理空值

Question

我正在尝试通过使用以下查询（例如将参数传递给存储过程以及排序方向和按列排序作为输入参数）来按列排序并在列中使用空值

ALTER PROCEDURE [dbo].[tp_SelectTransactionHistorySearch]
(
   @OffSetRowNo INT,     
   @FetchRowNo INT,
   @StatusSelection NVARCHAR(MAX),
   @IsReviewed Bit,
   @ProjectCaseNumber VARCHAR(MAX),
   @CostPageNumber VARCHAR(MAX),
   @TransactionTypeChange VARCHAR(MAX),
   @DescriptionChange VARCHAR(MAX),
   @TrasactionCreateOnBeginDate DATE,
   @TransactionCreatedOnEndDate DATE,
   @TransactionUpdatedOnBeginDate DATE,
   @TransactionUpdateOnEndDate DATE,
   @ItemID VARCHAR(MAX),
   @SortOrder VARCHAR(MAX),
   @SortByColumnName VARCHAR(MAX)
)
AS

  SELECT 
        TransactionID,IsReviewed,ItemID,CostPageNumber,Comments,
        CreatedBy,CreatedDateTime,UpdatedBy,UpdatedDateTime,
        TransactionDescription,TransactionTypeID,PROJCASE,
        TransactionStatusID, TransactionStatusTypeName,
        TransactionStatusTypeDescription,    
        TransactionTypeName, TransactionTypeDescription,
        COUNT(*) OVER () as TotalCount
 FROM
 ( //select
  //  union
  //  select
  //  union  
   //like select statement from union results
 ) ResultSet
      //here i am doing sorting 
     ORDER BY
 CASE @SortOrder 
    WHEN 'ASC' THEN  
       CASE @SortByColumnName
         WHEN 'TransactionID' THEN CONVERT(VARCHAR(MAX), ResultSet.TransactionID)
         WHEN 'ItemID' THEN CONVERT(VARCHAR(MAX), ResultSet.ItemID)
         WHEN 'CostPageNumber' THEN ResultSet.CostPageNumber
         WHEN 'Comments' THEN ResultSet.Comments
         WHEN 'CreatedBy' THEN ResultSet.CreatedBy
         WHEN 'CreatedDateTime' THEN  CONVERT(VARCHAR(MAX), ResultSet.CreatedDateTime)
         WHEN 'UpdatedBy' THEN ResultSet.UpdatedBy
         WHEN 'UpdatedDateTime' THEN  CONVERT(VARCHAR(MAX), ResultSet.UpdatedDateTime)
         WHEN 'TransactionDescription' THEN ResultSet.TransactionDescription
         WHEN 'TransactionTypeName' THEN ResultSet.TransactionTypeName
         WHEN 'PROJCASE' THEN ResultSet.PROJCASE
         WHEN 'TransactionStatusTypeName' THEN ResultSet.TransactionStatusTypeName
         WHEN 'TransactionStatusTypeDescription' THEN ResultSet.TransactionStatusTypeDescription
       END 
  END 
  ASC, 
 CASE @SortOrder 
    WHEN 'DESC' THEN              
       CASE @SortByColumnName
         WHEN 'TransactionID' THEN  CONVERT(VARCHAR(MAX), ResultSet.TransactionID)
         WHEN 'ItemID' THEN CONVERT(VARCHAR(MAX), ResultSet.ItemID)
         WHEN 'CostPageNumber' THEN ResultSet.CostPageNumber
         WHEN 'Comments' THEN ResultSet.Comments
         WHEN 'CreatedBy' THEN ResultSet.CreatedBy
         WHEN 'CreatedDateTime' THEN CONVERT(VARCHAR(MAX), ResultSet.CreatedDateTime)
         WHEN 'UpdatedBy' THEN ResultSet.UpdatedBy
         WHEN 'UpdatedDateTime' THEN CONVERT(VARCHAR(MAX), ResultSet.UpdatedDateTime)
         WHEN 'TransactionDescription' THEN ResultSet.TransactionDescription
         WHEN 'TransactionTypeName' THEN ResultSet.TransactionTypeName
         WHEN 'PROJCASE' THEN ResultSet.PROJCASE
         WHEN 'TransactionStatusTypeName' THEN ResultSet.TransactionStatusTypeName
         WHEN 'TransactionStatusTypeDescription' THEN ResultSet.TransactionStatusTypeDescription
       END 
 END 
 OFFSET ( @OffSetRowNo-1 ) * @FetchRowNo ROWS
    FETCH NEXT @FetchRowNo ROWS ONLY

在这里不使用任何 orderBy（排序方法）我得到two rows的结果即使它们是列中的空值但使用排序（即）OrderBy 我只能得到一行作为结果，我不知道如何处理空值使用 order by 时，但我尝试了以下语句

  WHEN ColumnB IS NULL THEN 1 ELSE 0 END ASC,

但是当应用这个时，我遇到语法错误....在这种情况下订购时，请提出任何想法如何处理空值.. 我使用的是 sql server 2012 版

提前谢谢了 ....

Answer 1

下面给出了动态排序顺序和排序字段的简化方案。

--TEST DATA
DECLARE @MYTable TABLE (EmpID INT, EmpName VARCHAR(10) , JoinDate DATETIME)

INSERT INTO @MYTable VALUES (1,'E1','1/1/2001');
INSERT INTO @MYTable VALUES (2,'E2','2/2/2002');
INSERT INTO @MYTable VALUES (3,'E3','5/5/2001');

--INPUT Parameters
DECLARE @SortParam VARCHAR(MAX)
SET @SortParam = 'JoinDate'

DECLARE @SortDirection VARCHAR(MAX)
SET @SortDirection = 'DESC'


--@RankTypeID Variable
DECLARE @RankTypeID  INT

--EMPNAME
IF (@SortParam = 'EmpName' AND @SortDirection = 'ASC')
BEGIN 
    SET @RankTypeID = 1 
END

IF (@SortParam = 'EmpName' AND @SortDirection = 'DESC')
BEGIN
    SET @RankTypeID = -1    
END

--EmpID
IF (@SortParam = 'EmpID' AND @SortDirection = 'ASC')
BEGIN 
    SET @RankTypeID = 2 
END

IF (@SortParam = 'EmpID' AND @SortDirection = 'DESC')
BEGIN
    SET @RankTypeID = -2
END

--JoinDate
IF (@SortParam = 'JoinDate' AND @SortDirection = 'ASC')
BEGIN 
    SET @RankTypeID = 3 
END

IF (@SortParam = 'JoinDate' AND @SortDirection = 'DESC')
BEGIN
    SET @RankTypeID = -3
END


-- SELECT
SELECT * 
FROM @MYTable M
ORDER BY 
        CASE @RankTypeID WHEN 1 then EmpName ELSE null end ASC,
        CASE @RankTypeID WHEN -1 then EmpName ELSE null end DESC,

        CASE @RankTypeID WHEN 2 then [EmpID] else null end ASC ,
        CASE @RankTypeID WHEN -2 then [EmpID] else null end DESC ,

        CASE @RankTypeID WHEN 3 then JoinDate else null end  ASC,
        CASE @RankTypeID WHEN -3 then JoinDate else null end  DESC


--END

Answer 2

您是否尝试过使用内置ISNULL()功能？

ISNULL(ColumnB, 1)