PostgreSQL "DESCRIBE TABLE"

Question

How do you perform the equivalent of Oracle's DESCRIBE TABLE in PostgreSQL with psql command?

Answer 1

Try this (in the psql command-line tool):

\d+ tablename

See the manual for more info.

Answer 2

In addition to the PostgreSQL way (\d 'something' or \dt 'table' or \ds 'sequence' and so on)

The SQL standard way, as shown here:

select column_name, data_type, character_maximum_length, column_default, is_nullable
from INFORMATION_SCHEMA.COLUMNS where table_name = '<name of table>';

It's supported by many db engines.

Answer 3

If you want to obtain it from query instead of psql, you can query the catalog schema. Here's a complex query that does that:

SELECT  
    f.attnum AS number,  
    f.attname AS name,  
    f.attnum,  
    f.attnotnull AS notnull,  
    pg_catalog.format_type(f.atttypid,f.atttypmod) AS type,  
    CASE  
        WHEN p.contype = 'p' THEN 't'  
        ELSE 'f'  
    END AS primarykey,  
    CASE  
        WHEN p.contype = 'u' THEN 't'  
        ELSE 'f'
    END AS uniquekey,
    CASE
        WHEN p.contype = 'f' THEN g.relname
    END AS foreignkey,
    CASE
        WHEN p.contype = 'f' THEN p.confkey
    END AS foreignkey_fieldnum,
    CASE
        WHEN p.contype = 'f' THEN g.relname
    END AS foreignkey,
    CASE
        WHEN p.contype = 'f' THEN p.conkey
    END AS foreignkey_connnum,
    CASE
        WHEN f.atthasdef = 't' THEN pg_get_expr(d.adbin, d.adrelid)
    END AS default
FROM pg_attribute f  
    JOIN pg_class c ON c.oid = f.attrelid  
    JOIN pg_type t ON t.oid = f.atttypid  
    LEFT JOIN pg_attrdef d ON d.adrelid = c.oid AND d.adnum = f.attnum  
    LEFT JOIN pg_namespace n ON n.oid = c.relnamespace  
    LEFT JOIN pg_constraint p ON p.conrelid = c.oid AND f.attnum = ANY (p.conkey)  
    LEFT JOIN pg_class AS g ON p.confrelid = g.oid  
WHERE c.relkind = 'r'::char  
    AND n.nspname = '%s'  -- Replace with Schema name  
    AND c.relname = '%s'  -- Replace with table name  
    AND f.attnum > 0 ORDER BY number
;

It's pretty complex but it does show you the power and flexibility of the PostgreSQL system catalog and should get you on your way to pg_catalog mastery ;-). Be sure to change out the %s's in the query. The first is Schema and the second is the table name.

Answer 4

You can do that with a psql slash command:

 \d myTable describe table

It also works for other objects:

 \d myView describe view
 \d myIndex describe index
 \d mySequence describe sequence

Source: faqs.org

Answer 5

This should be the solution:

SELECT * FROM information_schema.columns
WHERE table_schema = 'your_schema'
   AND table_name   = 'your_table'

Answer 6

The psql equivalent of DESCRIBE TABLE is \d table.

See the psql portion of the PostgreSQL manual for more details.

Answer 7

You may do a \d *search pattern * with asterisks to find tables that match the search pattern you're interested in.

Answer 8

In addition to the command line \d+ <table_name> you already found, you could also use the information-schema to look up the column data, using info_schema.columns

SELECT *
FROM info_schema.columns
WHERE table_schema = 'your_schema'
AND table_name   = 'your_table'

Answer 9

Use the following SQL statement

SELECT DATA_TYPE 
FROM INFORMATION_SCHEMA.COLUMNS 
WHERE table_name = 'tbl_name' 
AND COLUMN_NAME = 'col_name'

If you replace tbl_name and col_name, it displays data type of the particular coloumn that you looking for.

Answer 10

You can use this :

SELECT attname 
FROM pg_attribute,pg_class 
WHERE attrelid=pg_class.oid 
AND relname='TableName' 
AND attstattarget <>0; 

Answer 11

\dt can describe multiple tables simply:

\dt

\dt can describe a single table simply:

\dt <table>

\d can describe multiple tables in detail:

\d <table> <table>

\d+ can describe multiple tables in more detail:

\d+ <table> <table>

In addition, pg_tables can describe a table simply:

SELECT * FROM pg_tables WHERE tablename = '<table>';

And, information_schema.columns can describe a tables in much more detail:

SELECT * FROM information_schema.columns WHERE table_name = '<table>';

Answer 12

In MySQL , DESCRIBE table_name

---

In PostgreSQL , \d table_name

---

Or , you can use this long command:

SELECT
        a.attname AS Field,
        t.typname || '(' || a.atttypmod || ')' AS Type,
        CASE WHEN a.attnotnull = 't' THEN 'YES' ELSE 'NO' END AS Null,
        CASE WHEN r.contype = 'p' THEN 'PRI' ELSE '' END AS Key,
        (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid), '\'(.*)\'')
                FROM
                        pg_catalog.pg_attrdef d
                WHERE
                        d.adrelid = a.attrelid
                        AND d.adnum = a.attnum
                        AND a.atthasdef) AS Default,
        '' as Extras
FROM
        pg_class c 
        JOIN pg_attribute a ON a.attrelid = c.oid
        JOIN pg_type t ON a.atttypid = t.oid
        LEFT JOIN pg_catalog.pg_constraint r ON c.oid = r.conrelid 
                AND r.conname = a.attname
WHERE
        c.relname = 'tablename'
        AND a.attnum > 0

ORDER BY a.attnum

Answer 13

This variation of the query (as explained in other answers) worked for me.

SELECT
 COLUMN_NAME
FROM
 information_schema.COLUMNS
WHERE
 TABLE_NAME = 'city';

It's described here in details: http://www.postgresqltutorial.com/postgresql-describe-table/

Answer 14

To improve on the other answer's SQL query (which is great!), here is a revised query. It also includes constraint names, inheritance information, and a data types broken into it's constituent parts (type, length, precision, scale). It also filters out columns that have been dropped (which still exist in the database).

SELECT
    n.nspname as schema,
    c.relname as table,
    f.attname as column,  
    f.attnum as column_id,  
    f.attnotnull as not_null,
    f.attislocal not_inherited,
    f.attinhcount inheritance_count,
    pg_catalog.format_type(f.atttypid,f.atttypmod) AS data_type_full,
    t.typname AS data_type_name,
    CASE  
        WHEN f.atttypmod >= 0 AND t.typname <> 'numeric'THEN (f.atttypmod - 4) --first 4 bytes are for storing actual length of data
    END AS data_type_length, 
    CASE  
        WHEN t.typname = 'numeric' THEN (((f.atttypmod - 4) >> 16) & 65535)
    END AS numeric_precision,   
    CASE  
        WHEN t.typname = 'numeric' THEN ((f.atttypmod - 4)& 65535 )
    END AS numeric_scale,       
    CASE  
        WHEN p.contype = 'p' THEN 't'  
        ELSE 'f'  
    END AS is_primary_key,  
    CASE
        WHEN p.contype = 'p' THEN p.conname
    END AS primary_key_name,
    CASE  
        WHEN p.contype = 'u' THEN 't'  
        ELSE 'f'
    END AS is_unique_key,
    CASE
        WHEN p.contype = 'u' THEN p.conname
    END AS unique_key_name,
    CASE
        WHEN p.contype = 'f' THEN 't'
        ELSE 'f'
    END AS is_foreign_key,
    CASE
        WHEN p.contype = 'f' THEN p.conname
    END AS foreignkey_name,
    CASE
        WHEN p.contype = 'f' THEN p.confkey
    END AS foreign_key_columnid,
    CASE
        WHEN p.contype = 'f' THEN g.relname
    END AS foreign_key_table,
    CASE
        WHEN p.contype = 'f' THEN p.conkey
    END AS foreign_key_local_column_id,
    CASE
        WHEN f.atthasdef = 't' THEN d.adsrc
    END AS default_value
FROM pg_attribute f  
    JOIN pg_class c ON c.oid = f.attrelid  
    JOIN pg_type t ON t.oid = f.atttypid  
    LEFT JOIN pg_attrdef d ON d.adrelid = c.oid AND d.adnum = f.attnum  
    LEFT JOIN pg_namespace n ON n.oid = c.relnamespace  
    LEFT JOIN pg_constraint p ON p.conrelid = c.oid AND f.attnum = ANY (p.conkey)  
    LEFT JOIN pg_class AS g ON p.confrelid = g.oid  
WHERE c.relkind = 'r'::char  
    AND f.attisdropped = false
    AND n.nspname = '%s'  -- Replace with Schema name  
    AND c.relname = '%s'  -- Replace with table name  
    AND f.attnum > 0 
ORDER BY f.attnum
;

Answer 15

In postgres \d is used to describe the table structure.

e.g. \d schema_name.table_name

this command will provide you the basic info of table such as, columns, type and modifiers.

If you want more info about table use

\d+ schema_name.table_name

this will give you extra info such as, storage, stats target and description

Answer 16

When your table name starts with a capital letter you should put your table name in the quotation.

Example: \d "Users"

Answer 17

You can also check using below query

Select * from schema_name.table_name limit 0;

Expmple : My table has 2 columns name and pwd. Giving screenshot below.

*Using PG admin3

Answer 18

The best way to describe a table such as a column, type, modifiers of columns, etc.

\d+ tablename or \d tablename

Answer 19

Use this command 

\d table name

like 

\d queuerecords

             Table "public.queuerecords"
  Column   |            Type             | Modifiers
-----------+-----------------------------+-----------
 id        | uuid                        | not null
 endtime   | timestamp without time zone |
 payload   | text                        |
 queueid   | text                        |
 starttime | timestamp without time zone |
 status    | text                        |

Answer 20

When your table is not part of the default schema, you should write:

\d+ schema_name.table_name

Otherwise, you would get the error saying that "the relation doesn not exist."

Answer 21

To get description use,

SELECT  column_name, data_type, is_nullable FROM information_schema.columns WHERE table_name = 'table_name';

To get the indexes use,

SELECT indexname, indexdef FROM pg_indexes WHERE schemaname = 'public' AND tablename = 'table_name' ORDER BY indexname;

Answer 22

1) PostgreSQL DESCRIBE TABLE using psql

In psql command line tool, \d table_name or \d+ table_name to find the information on columns of a table

2) PostgreSQL DESCRIBE TABLE using information_schema

SELECT statement to query the column_names,datatype,character maximum length of the columns table in the information_schema database;

SELECT COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH from INFORMATION_SCHEMA.COLUMNS where table_name = 'tablename';

For more information https://www.postgresqltutorial.com/postgresql-describe-table/

Answer 23

/dt is the commad which lists you all the tables present in a database. using
/d command and /d+ we can get the details of a table. The sysntax will be like
* /d table_name (or) \d+ table_name

Answer 24

I'll add the pg_dump command even thou the psql command was requested. because it generate an output more common to previous MySQl users.

# sudo -u postgres pg_dump --table=my_table_name --schema-only mydb

Answer 25

I worked out the following script for get table schema.

'CREATE TABLE ' || 'yourschema.yourtable' || E'\n(\n' ||
array_to_string(
array_agg(
'    ' || column_expr
)
, E',\n'
) || E'\n);\n'
from
(
SELECT '    ' || column_name || ' ' || data_type || 
coalesce('(' || character_maximum_length || ')', '') || 
case when is_nullable = 'YES' then ' NULL' else ' NOT NULL' end as column_expr
FROM information_schema.columns
WHERE table_schema || '.' || table_name = 'yourschema.yourtable'
ORDER BY ordinal_position
) column_list;