How to get a list column names and datatype of a table in PostgreSQL?

Question

With the following query, we can get a list of column names and datatype of a table in PostgreSQL.

Answer 1

SELECT
        a.attname as "Column",
        pg_catalog.format_type(a.atttypid, a.atttypmod) as "Datatype"
    FROM
        pg_catalog.pg_attribute a
    WHERE
        a.attnum > 0
        AND NOT a.attisdropped
        AND a.attrelid = (
            SELECT c.oid
            FROM pg_catalog.pg_class c
                LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
            WHERE c.relname ~ '^(hello world)$'
                AND pg_catalog.pg_table_is_visible(c.oid)
        );

More info on it : http://www.postgresql.org/docs/9.3/static/catalog-pg-attribute.html

Answer 2

Updated Pratik answer to support more schemas and nullables:

SELECT
    "pg_attribute".attname                                                    as "Column",
    pg_catalog.format_type("pg_attribute".atttypid, "pg_attribute".atttypmod) as "Datatype",

    not("pg_attribute".attnotnull) AS "Nullable"
FROM
    pg_catalog.pg_attribute "pg_attribute"
WHERE
    "pg_attribute".attnum > 0
    AND NOT "pg_attribute".attisdropped
    AND "pg_attribute".attrelid = (
        SELECT "pg_class".oid
        FROM pg_catalog.pg_class "pg_class"
            LEFT JOIN pg_catalog.pg_namespace "pg_namespace" ON "pg_namespace".oid = "pg_class".relnamespace
        WHERE
            "pg_namespace".nspname = 'schema'
            AND "pg_class".relname = 'table'
    );

Answer 3

select column_name,data_type 
from information_schema.columns 
where table_name = 'table_name';

with the above query you can columns and its datatype

Answer 4

To make this topic 'more complete'.

I required the column names and data types on a SELECT statement (not a table).

If you want to do this on a SELECT statement instead of an actual existing table, you can do the following:

DROP TABLE IF EXISTS abc;
CREATE TEMPORARY TABLE abc AS
-- your select statement here!
SELECT 
    *
FROM foo
-- end your select statement
;

select column_name, data_type 
from information_schema.columns 
where table_name = 'abc';
DROP IF EXISTS abc;

Short explanation, it makes a (temp) table of your select statement, which you can 'call' upon via the query provided by (among others) @a_horse_with_no_name and @selva.

Hope this helps.

Answer 5

A version that supports finding the column names and types of a table in a specific schema, and uses JOINs without any subqueries

SELECT
    pg_attribute.attname AS column_name,
    pg_catalog.format_type(pg_attribute.atttypid, pg_attribute.atttypmod) AS data_type
FROM
    pg_catalog.pg_attribute
INNER JOIN
    pg_catalog.pg_class ON pg_class.oid = pg_attribute.attrelid
INNER JOIN
    pg_catalog.pg_namespace ON pg_namespace.oid = pg_class.relnamespace
WHERE
    pg_attribute.attnum > 0
    AND NOT pg_attribute.attisdropped
    AND pg_namespace.nspname = 'my_schema'
    AND pg_class.relname = 'my_table'
ORDER BY
    attnum ASC;

Answer 6

Don't forget to add the schema name in case you have multiple schemas with the same table names.

SELECT column_name, data_type 
FROM information_schema.columns
WHERE table_name = 'your_table_name' AND table_schema = 'your_schema_name';

or using psql:

\d+ your_schema_name.your_table_name