PostgreSQL says “return and sql tuple descriptions are incompatible”

Question

I have the following data:

ID  CLASS   VALUE
1   NHB    700905.7243
1   HBW    164216.1311
1   HBO    700905.7243
2   NHB    146023.3792
2   HBW    89543.29         


        

Answer 1

This works for me on Postgres 9.3:

SELECT *
FROM   crosstab (
 $$SELECT id, class, "value"
   FROM   _tlfd
   WHERE  class = ANY ('{HBW, HBO, NHB}')
   ORDER  BY 1,2$$
   ) AS t (
        class int,                   -- needs a table alias!
        "HBW" float8,                -- resulting columns are double precision!
        "HBO" float8,
        "NHB" float8
        -- "value" double precision  -- column does not exist in result!
    );

Produces the desired output.

Essential changes

• the table alias (bold t)
• the removed surplus column "value"
• the correct data type for your data columns (double precision a.k.a. float8)

The rest is a matter of taste and style. I wouldn't use value as column name though, since it is a reserved word in SQL.

Basics for crosstab() queries here:

• PostgreSQL Crosstab Query