SQL UPDATE row Number | 易学教程

问题

I have a table serviceClusters with a column identity(1590 values). Then I have another table serviceClustersNew with the columns ID, text and comment. In this table, I have some values for text and comment, the ID is always 1. Here an example for the table:

[1, dummy1, hello1;

1, dummy2, hello2;

1, dummy3, hello3;

etc.]

WhaI want now for the values in the column ID is the continuing index of the table serviceClusters plus the current Row number: In our case, this would be 1591, 1592 and 1593.

I tried to solve the problem like this: First I updated the column ID with the maximum value, then I tryed to add the row number, but this doesnt work:

-- Update ID to the maximum value 1590
UPDATE serviceClustersNew 
SET ID = (SELECT MAX(ID) FROM serviceClusters);
-- This command returns the correct values 1591, 1592 and 1593
SELECT ID+ROW_NUMBER() OVER (ORDER BY Text_ID) AS RowNumber 
FROM serviceClustersNew
-- But I'm not able to update the table with this command
UPDATE serviceClustersNew 
SET ID = (SELECT ID+ROW_NUMBER() OVER (ORDER BY Text_ID) AS RowNumber FROM
serviceClustersNew)

By sending the last command, I get the error "Syntax error: Ordered Analytical Functions are not allowed in subqueries.". Do you have any suggestions, how I could solve the problem? I know I could do it with a volatile table or by adding a column, but is there a way without creating a new table / altering the current table?

回答1:

You have to rewrite it using UPDATE FROM, the syntax is just a bit bulky:

UPDATE serviceClustersNew
FROM
 (
   SELECT text_id,
      (SELECT MAX(ID) FROM serviceClusters) +
      ROW_NUMBER() OVER (ORDER BY Text_ID) AS newID 
   FROM serviceClustersNew
 ) AS src
SET ID = newID
WHERE serviceClustersNew.Text_ID = src.Text_ID

回答2:

You are not dealing with a lot of data, so a correlated subquery can serve the same purpose:

UPDATE serviceClustersNew 
    SET ID = (select max(ID) from serviceClustersNew) +
             (select count(*)
              from serviceClustersNew scn2
              where scn2.Text_Id <= serviceClustersNew.TextId
             )

This assumes that the text_id is unique along the rows.

回答3:

Apparently you can update a base table through a CTE... had no idea. So, just change your last UPDATE statement to this, and you should be good. Just be sure to include any fields in the CTE that you desire to update.

;WITH cte_TEST AS 
( SELECT 
    ID,
    ID+ROW_NUMBER() OVER (ORDER BY TEXT_ID) AS RowNumber FROM serviceClustersNew)
UPDATE cte_TEST 
SET cte_TEST.ID = cte_TEST.RowNumber

Source: http://social.msdn.microsoft.com/Forums/sqlserver/en-US/ee06f451-c418-4bca-8288-010410e8cf14/update-table-using-rownumber-over

来源：https://stackoverflow.com/questions/17969517/sql-update-row-number

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sql

numbers

teradata