Question

I am trying to write a postgres query, which is with CASE statement. The query is as follows:

SELECT "State" AS x, count("Age Group") AS y from test.smp_state_survey where "State" IN 
(CASE 
        WHEN 'State' = 'State' THEN 'State 1','State 2','State 3'
        WHEN 'State' = 'District' THEN 'State 1'
    END) 
  group by x ORDER BY x,y 

The above query is showing syntax error at 'State' = 'State'

Whereas, when I executed the below query, i get the appropriate results:

SELECT "State" AS x, count("Age Group") AS y from test.smp_state_survey where "State" IN 
(CASE 
        WHEN 'State' = 'State' THEN 'State 1'
        WHEN 'State' = 'District' THEN 'State 1'
    END) 
  group by x ORDER BY x,y 

Please let me know what am I doing wrong.

Edit:

The value after THEN clause is dynamic and it may contain 1 or more values (From a multi select box). I want the query to be executed as

SELECT "State" AS x, count("Age Group") AS y from test.smp_state_survey where "State" IN 
('State 1','State 2','State 3') 
  group by x ORDER BY x,y 

Which runs exactly fine, but the problem is that CASE is not returning me the required string.

Answer 1

Your query should be like this, i hope this will work for you

SELECT  "State" AS x, count("Age Group") AS y from test.smp_state_survey where  
CASE  
        WHEN 'State' = 'State'  THEN  "State" IN  ('State 1' ,'State 3')
        WHEN 'State' = 'District' THEN "State" IN  ('District 1')
    END
  group by x ORDER BY x,y