如何转置 postgresql 中的表值？

Question

How can I transpose these values to take this table:

And make it look like this:

There's no Pivot function that I can use in postgresql and every time I try the crosstab function, I keep getting an error in my code. Let's pretend that my table is called select * from TAttributes

Answer 1

Use conditional aggregation, which in Postgres means filter :

select id,
       max(attributenumber) filter (where attributeid = 2000),
       max(attributenumber) filter (where attributeid = 2001),
       max(attributenumber) filter (where attributeid = 2002),
       max(attributenumber) filter (where attributeid = 2003)
from t
group by id;

Here is a db<>fiddle.

Answer 2

Try this:

SELECT id,  
    MAX((SELECT attributenumber FROM public.t WHERE ext_t.id = id AND ext_t.attribuiteid = attribuiteid AND attribuiteid = 2000)) AS '2000',
    MAX((SELECT attributenumber FROM public.t WHERE ext_t.id = id AND ext_t.attribuiteid = attribuiteid AND attribuiteid = 2001)) AS '2001',
    MAX((SELECT attributenumber FROM public.t WHERE ext_t.id = id AND ext_t.attribuiteid = attribuiteid AND attribuiteid = 2002)) AS '2002',
    MAX((SELECT attributenumber FROM public.t WHERE ext_t.id = id AND ext_t.attribuiteid = attribuiteid AND attribuiteid = 2003)) AS '2003' 
FROM public.t ext_t GROUP BY id