Question

I need to update the next column to the column that contains an specific number.

The ff are columns in the table C.

C1_K | C1_ID | C2_K | C2_ID | C3_K | C3_ID

Logic:

• Look for where number 5 is found is it in C1_K OR C2_K OR C3_K.
• If it is in C1_K then select the text value C1_ID.
• If it is in C2_K then select the text value C2_ID.
• If it is in C3_K then select the text value C3_ID.

Please advice. I need to update the column next to the matching K column. Thanks.

Note:

• All C*_K columns contains unique numbers.
• All C*_ID columns contains unique text. (these are names)

Sample Data:

 154 | NULL | 155 | SantoRyUu | 156 | NULL

If 155 is chosen SantoRyUu will be updated.

Answer 1

(Design problems aside.)

You have to mention the columns by name, since SQL Server doesn’t have syntax for “next to.” You may be able to do this with dynamic SQL, but yuck. Here is one possibility:

CREATE TABLE dbo.C
(
  C1_K  INT, 
  C1_ID VARCHAR(32), 
  C2_K  INT, 
  C2_ID VARCHAR(32), 
  C3_K  INT, 
  C3_ID VARCHAR(32)
);

INSERT dbo.C(C1_K, C2_K, C3_k)
SELECT 5,1,2
UNION ALL SELECT 2,5,7
UNION ALL SELECT 3,4,6;

DECLARE @MagicNumber INT;
SET @MagicNumber = 5;

UPDATE dbo.C SET 
 C1_ID = CASE C1_K WHEN @MagicNumber THEN 'yes' ELSE C1_ID END,
 C2_ID = CASE C2_K WHEN @MagicNumber THEN 'yes' ELSE C2_ID END,
 C3_ID = CASE C3_K WHEN @MagicNumber THEN 'yes' ELSE C3_ID END;

SELECT * FROM dbo.C;

Results:

C1_K  C1_ID  C2_K  C2_ID  C3_K  C3_ID
----  -----  ----  -----  ----  -----
5     yes    1     NULL   2     NULL
2     NULL   5     yes    7     NULL
3     NULL   4     NULL   6     NULL