How do you perform the equivalent of Oracle's DESCRIBE TABLE in PostgreSQL with psql command?
26 Answers
12 Comments
+ is really clutch, as PostgresSQL 9 only gives the in-depth description for views when you do \d+ table_name, rather than the simple \d table_namepsql -E is handy to get the sql that implements \d+ and similar (for use outside of the psql prompt)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>'
order by ordinal_position;
It's supported by many db engines.
12 Comments
\d+ does not. This is the best answer IMOIf 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.
7 Comments
format_type() will include any modifiers attached to the type, e.g. numeric(6,2); whereas information_schema.columns will only report the base type of numeric.d.adsrc with pg_get_expr(d.adbin, d.adrelid) works fineYou can do that with the \d psql slash command:
-- describe table
\d myTable
It also works for other objects:
-- describe view
\d myView
-- describe index
\d myIndex
-- describe sequence
\d mySequence
Source: faqs.org
2 Comments
This should be the solution:
SELECT * FROM information_schema.columns
WHERE table_schema = 'your_schema'
AND table_name = 'your_table'
1 Comment
The psql equivalent of DESCRIBE TABLE is \d table.
See the psql portion of the PostgreSQL manual for more details.
2 Comments
\c databasename rather than use databasename (for those coming from MySQL like myself :-). Without \c databasename first, \d tablename produces No relations found. message and nothing more.\d databasename.tablename too. With proper quoting if necessary, i.e. \d "DatabaseName"."TableName", if your names are not all lowercase.You may do a \d *search pattern * with asterisks to find tables that match the search pattern you're interested in.
2 Comments
\d *"<SubString>"*. That is, the double quotes must be inside the asterisks. Though, if you just want the list of tables then you want to use \dtIn 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'
1 Comment
FROM info_schema.columns didn't work for me I had to use from information_schema.columns, not sure if that's a typo in your answer or some implementation issue at my end.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.
2 Comments
\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>';
3 Comments
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
Comments
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/
Comments
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
;
Comments
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
Comments
When your table name starts with a capital letter you should put your table name in the quotation.
Example: \d "Users"
1 Comment
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
2 Comments
LIMIT clause is evaluated after both FROM and SELECT; therefore, this query would take a long time to finish if the table in question is large.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 |
Comments
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/
Comments
A variant of https://stackoverflow.com/a/109337/324105 which more closely mimics the output of \d <table> (in postgres 14 at least),
but without the (often-lengthy) "Indexes: ... Foreign-key constraints: ... Referenced by: ..." lists that follow (which personally I rarely want to see, and could do so with \d+ on the occasions when I do).
SELECT column_name AS "Column",
CASE WHEN character_maximum_length IS NOT NULL
THEN CONCAT(data_type, '(', character_maximum_length, ')')
ELSE data_type
END AS "Type",
collation_name as "Collation",
CASE WHEN is_nullable = 'NO' THEN 'not null'
WHEN is_nullable = 'YES' THEN NULL
ELSE is_nullable
END AS "Nullable",
column_default AS "Default"
FROM information_schema.columns
WHERE table_name = '%s'
-- AND table_schema = '%s'
ORDER BY ordinal_position;
I've only included the Collation column for the purposes of writing this answer, and I'm not sure whether that's correct. When I compare this vs \d for pg_catalog.pg_type I'm seeing the typname column with a collation of C in my query output, but null in the \d output. I don't know why that is, and I haven't looked into it further because I'm not going to be showing this column in my own use-case.
There may be other differences (e.g. for pg_type.typacl I see a Type of ARRAY from this, but aclitem[] from \d), but for my normal purposes I believe this will be more than suitable -- and for everything else there's \d+.
It's a shame that \d isn't configurable.
Comments
I worked out the following script for get table schema.
select 'CREATE TABLE IF NOT EXISTS ' || t.table_schema || '.' || t.table_name || E'\n(\n'
|| (
select
array_to_string(
array_agg(
' ' || column_expr
)
, E',\n'
)
from (
SELECT ' ' || c.column_name || ' ' || c.data_type ||
coalesce('(' || c.character_maximum_length || ')', '') ||
case when c.is_nullable = 'YES' then ' NULL' else ' NOT NULL' end as column_expr
FROM information_schema.columns c
WHERE c.table_schema = t.table_schema and c.table_name = t.table_name
ORDER BY c.ordinal_position
) column_list
)
|| E'\n);\n' as table_definition
from information_schema.tables t
where t.table_schema = 'yourschema'
and t.table_name = 'yourtable';
