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Update row with data from another row in the same table

Posted by: admin November 1, 2017 Leave a comment

Questions:

I’ve got a table which looks something like this

ID   |   NAME    |  VALUE  |
----------------------------
 1   |   Test    |  VALUE1 |
 2   |   Test2   |  VALUE2 |
 1   |   Test2   |         |
 4   |   Test    |         |
 1   |   Test3   |  VALUE3 |

I’m looking for a way to update the values ‘Test2’ and ‘Test’ with the data from other rows in the ‘VALUE’ column with the same ‘NAME’ (The ID is not unique here, a composite key of the ID and NAME make a row unique). For example, the output I’m looking for is:

ID   |   NAME    |  VALUE  |
----------------------------
 1   |   Test    |  VALUE1 |
 2   |   Test2   |  VALUE2 |
 1   |   Test2   |  VALUE2 |
 4   |   Test    |  VALUE1 |
 1   |   Test3   |  VALUE3 |

If it was in another table I’d be fine, but I’m at a loss as to how I can reference a different row within the current table with the same NAME value.

Update

After modifying manji query, below is the query I used for a working solution. Thanks all!

UPDATE data_table dt1, data_table dt2 
SET dt1.VALUE = dt2.VALUE 
WHERE dt1.NAME = dt2.NAME AND dt1.VALUE = '' AND dt2.VALUE != '' 
Answers:

Try this:

UPDATE data_table t, (SELECT DISTINCT ID, NAME, VALUE
                        FROM data_table
                       WHERE VALUE IS NOT NULL AND VALUE != '') t1
   SET t.VALUE = t1.VALUE
 WHERE t.ID = t1.ID
   AND t.NAME = t1.NAME

Questions:
Answers:

Here’s my go:

UPDATE test as t1 
    INNER JOIN test as t2 ON 
        t1.NAME = t2.NAME AND 
        t2.value IS NOT NULL 
SET t1.VALUE = t2.VALUE;

EDIT: Removed superfluous t1.id != t2.id condition.

Questions:
Answers:
Update MyTable
Set Value = (
                Select Min( T2.Value )
                From MyTable As T2
                Where T2.Id <> MyTable.Id
                    And T2.Name = MyTable.Name
                )
Where ( Value Is Null Or Value = '' )
    And Exists  (
                Select 1
                From MyTable As T3
                Where T3.Id <> MyTable.Id
                    And T3.Name = MyTable.Name
                )

Questions:
Answers:
UPDATE financialyear
   SET firstsemfrom = dt2.firstsemfrom,
       firstsemto = dt2.firstsemto,
       secondsemfrom = dt2.secondsemfrom,
       secondsemto = dt2.secondsemto
  from financialyear dt2
 WHERE financialyear.financialyearkey = 141
   AND dt2.financialyearkey = 140

Questions:
Answers:

If you just need to insert a new row with a data from another row,

    insert into ORDER_ITEM select * from ORDER_ITEM where ITEM_NUMBER =123;