问题
How do you perform the equivalent of Oracle\'s DESCRIBE TABLE in PostgreSQL (using the psql command)?
回答1:
Try this (in the psql command-line tool):
\d+ tablename
See the manual for more info.
回答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
from INFORMATION_SCHEMA.COLUMNS where table_name = '<name of table>';
It's supported by many db engines.
回答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 d.adsrc
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.
回答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
回答5:
The psql equivalent of DESCRIBE TABLE is \d table.
See the psql portion of the PostgreSQL manual for more details.
回答6:
You may do a \d *search pattern * with asterisks to find tables that match the search pattern you're interested in.
回答7:
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'
回答8:
This should be the solution:
SELECT * FROM information_schema.columns
WHERE table_schema = 'your_schema'
AND table_name = 'your_table'
回答9:
You can use this :
SELECT attname
FROM pg_attribute,pg_class
WHERE attrelid=pg_class.oid
AND relname='TableName'
AND attstattarget <>0;
回答10:
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.
回答11:
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/
回答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
回答13:
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
;
回答14:
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
回答15:
The best way to describe a table such as a column, type, modifiers of columns, etc.
\d+ tablename or \d tablename
回答16:
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 |
回答17:
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
回答18:
/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
回答19:
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;
来源：https://stackoverflow.com/questions/109325/postgresql-describe-table