PostgreSQL “DESCRIBE TABLE”

2019-01-02 19:14发布

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

18条回答
听够珍惜
2楼-- · 2019-01-02 19:27

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/

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人气声优
3楼-- · 2019-01-02 19:28

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

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荒废的爱情
4楼-- · 2019-01-02 19:29

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'
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临风纵饮
5楼-- · 2019-01-02 19:29

You can use this :

SELECT attname 
FROM pg_attribute,pg_class 
WHERE attrelid=pg_class.oid 
AND relname='TableName' 
AND attstattarget <>0; 
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深知你不懂我心
6楼-- · 2019-01-02 19:30

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
;
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伤终究还是伤i
7楼-- · 2019-01-02 19:30
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
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