Need an SQL query to map column value to column name

Question

I have following table structure (Table Name is Questions)

c1   c2   c3  Selection

X    Y    Z   2

A    B    C   3

Here c1,c2,c3 and Selection are column names. I want to retrieve value of c1 or c2 or c3 on the basis of value of column Selection. Eg. If Selection value is 2 then I want corresponding value of c2 column i.e. Y. If Selection value is 3 then it should select value of c3 column which is C here.

Please help me in forming Select Sql query here. I tried myself but was not able to find correct solution.

Thanks in advance

http://dev.mysql.com/doc/refman/5.5/en/control-flow-functions.html#operator_case — Joddy, Jan 06 '13 at 06:38
See [mysql field name from variable](http://stackoverflow.com/questions/4428761/mysql-field-name-from-variable) — Joop Eggen, Jan 06 '13 at 06:41

sourcecode · Answer 1 · 2013-01-06T06:45:28.670

2

you have to use CASE's or IF's

   select if(selection=2 ,b,if(selection=3,c,a)) from Table1 ;

see here for example ... link

edited Jan 06 '13 at 06:45

answered Jan 06 '13 at 06:39

sourcecode

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score 2 · Accepted Answer · answered Jan 06 '13 at 06:41

2

SELECT  CASE Selection
            WHEN 1 THEN c1
            WHEN 2 THEN c2
            ELSE c3
        END val
FROM    tableName

answered Jan 06 '13 at 06:41

John Woo

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thanks mate..this is what I wanted...I really appreciate your quick understanding of question and quick reply.... :) – Sonu Jan 06 '13 at 06:50

score 0 · Answer 3 · answered Jan 06 '13 at 06:38

0

This is very simple just run a simple query and it will return all the columns then you should use the appropriate column.

SELECT * FROM mytable WHERE selection = 'yourvalue'

answered Jan 06 '13 at 06:38

Muhammad Raheel

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Need an SQL query to map column value to column name

3 Answers3