如何在T-sql中使用逗号分隔的1列值或sql语句中生成多行

Question

ColumnName  IsOrdered    Seq_ID
ABC          2              2
DEF          1              1
GHI          0             NULL
JKL          1              4
MNO          1              3
PQR          0              5

I have a table (table1) in the database with above values stored in it.

Note: -

I. Is_Ordered column : 2 --> Desc; 1 --> Asc; 0 --> Default.

II. Seq_ID column : Column names 'order by' sequence

These values are stored in the above table by user.(ie on User interface). I want to produce a 'order by' clause from the multiple rows to a single statement with comma ',' seperated (one single column).

eg: select * from Table1 order by DEF asc, ABC desc, MNO asc, JKL asc

Here I want to write a sql statement to produce just the order by statement as above shown ie (order by DEF asc, ABC desc, MNO asc, JKL asc)

Here you will notice that GHI column and PQR columns are not included since these two are not selected in the order by selections in the user interface.

I thank you in advance who tried to understand my question and given an appropriate solution for this.

Answer 1

Hope this helps

DECLARE @OrderBySetting VARCHAR(max) = ''
DECLARE @OrderByString VARCHAR(max) = ''

DECLARE MY_CURSOR CURSOR
FOR  SELECT  ColumnName + ' ' + 
case IsOrdered  
    WHEN 1 THEN 'ASC'
    WHEN 2 THEN 'DESC'
    END
    + ','
FROM         Table1
WHERE     (IsOrdered <> 0)
ORDER BY Seq_ID DESC

OPEN My_Cursor 

Fetch NEXT FROM MY_Cursor INTO @OrderBySetting

WHILE @@FETCH_STATUS = 0
BEGIN
    SET @OrderByString = @OrderBySetting + @OrderByString


FETCH NEXT FROM MY_Cursor INTO @OrderBySetting
END
CLOSE MY_Cursor
DEALLOCATE MY_Cursor

SET @OrderByString = 'SELECT * FROM TABLE1 ORDER BY ' + SUBSTRING(@OrderByString, 1, LEN(@OrderByString)-1)

Answer 2

Here you go (may need to add a CAST)

SELECT
    'ORDER BY ' +
      SUBSTRING(
      (
      SELECT
          ',' + ColumnName + 
               CASE IsOrdered  
                 WHEN 1 THEN 'ASC'
                 WHEN 2 THEN 'DESC'
               END
      FROM
          MyTable
      WHERE
          IsOrdered > 0 -- why have "IsIncluded" column ?
      ORDER BY
          Seq_ID
      FOR XML PATH ('')
      )
      , 2, 7999)