Обсуждение: PG Unpivot ?

On Mon, Nov 03, 2025 at 12:18:55PM -0500, dfgpostgres wrote:
> psql (13.2, server 15.3) on linux
> 
> I think they call this "unpivot" in MSSQL ?
> 
> How can I get an sql query to return  one line per column with... an ID,
> column name and value.  the ctid for the id field is fine.
> 
> Example:
> dvdb=# create table unpivot (intcol integer, floatcol float, strcol
> varchar);
> CREATE TABLE
> dvdb=# insert into unpivot (intcol,floatcol,strcol) values
> (1,1.1,'one'),(2,2.2,'two'),(3,3.3,'three');
> INSERT 0 3
> dvdb=# select * from unpivot;
>  intcol | floatcol | strcol
> --------+----------+--------
>       1 |      1.1 | one
>       2 |      2.2 | two
>       3 |      3.3 | three
> (3 rows)
> I want 9 records returned, each row with 3 cols, 1st col is the ctid,
> second is the column name, third is the val.

I think it should work:

select u.ctid, e.* from unpivot u, to_jsonb(u) j, jsonb_each_text(j) e;

Best regards,

depesz

dfgpostgres <dfgpostgres3@gmail.com> writes:
> I want 9 records returned, each row with 3 cols, 1st col is the ctid,
> second is the column name, third is the val.

Perhaps psql's "expanded" mode is close enough?

regression=# \x
Expanded display is on.
regression=# select * from unpivot;
-[ RECORD 1 ]---
intcol   | 1
floatcol | 1.1
strcol   | one
-[ RECORD 2 ]---
intcol   | 2
floatcol | 2.2
strcol   | two
-[ RECORD 3 ]---
intcol   | 3
floatcol | 3.3
strcol   | three

PS: I do not advise relying on ctid as a row identifier.
Use a proper primary key.

            regards, tom lane