Set case text in postgres sql

Question

I have this query.

Select '1' as "Test" , (CASE WHEN (True) Then '2' ELSE '3' END)

Id   case text
1     2

I want case text to be Two when true i.e.

   Id    Two
    1     2

And When Sql is

Select '1' as "Test" , (CASE WHEN (False) Then '2' ELSE '3' END)

Id    Three
 1     3

As will not fix my issue

  Select '1' as "Test" , (CASE WHEN (True) Then '2' ELSE '3' END) as Two/Three.

Because at once true or false will be output. When true then I want Two as column name and When false I want three. For now I have given it hard coded.

I will get true false based on some BI tool parameter. I have just given example above — Manjay_TBAG
– Manjay_TBAG, Commented Sep 16, 2016 at 9:12
try this remove that slash in between Two/Threee Select '1' as "Test" , (CASE WHEN (True) Then '2' ELSE '3' END) as Two_or_Three @TBAG — JYoThI
– JYoThI, Commented Sep 16, 2016 at 9:15

Laurenz Albe · Accepted Answer · 2016-09-16 09:38:10Z

2

You can't do this with SQL; there's no way to choose a column name based on the table content (what would that be if there were more than one rows in a table and the column values are different?).

What you could do is send a different query to the database for different values of the boolean parameter.

But the idea of choosing a column name based on the contents is weird. Do you really need to do that?

answered Sep 16, 2016 at 9:38

Laurenz Albe

257k22 gold badges314 silver badges390 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Gordon Linoff · Accepted Answer · 2016-09-16 09:52:26Z

1

You cannot do what you want with a simple SQL statement because a SELECT returns a set of columns, fixed in name and number. You could use dynamic SQL to change the name of the column.

However, why not just return two separate columns with flag values, if that is what you want:

Select '1' as "Test",
       (case when . . . then 1 else 0 end) as flag_2,
       (case when not (. . .) then 1 else 0 end) as flag_3

Then look at the value in the column rather than the presence of the column to get the information you want.

Or, put the value in the column:

Select '1' as "Test",
       (case when . . . then '2' else '3' end) as flag

answered Sep 16, 2016 at 9:52

Gordon Linoff

1.3m62 gold badges706 silver badges857 bronze badges

Collectives™ on Stack Overflow

Set case text in postgres sql

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related