PostgreSQL的“描述表”PostgreSQL的“描述表”(PostgreSQL “DESCR

2019-05-17 10:30发布

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你如何执行Oracle的相当于DESCRIBE TABLE （使用psql的命令）在PostgreSQL的？

Answer 1:

试试这个（在psql命令行工具）：

\d+ tablename

请参阅手册以获得更多信息。

Answer 2:

除了PostgreSQL的方式（\ d“某物”或\ DT“表”或\ DS“序列”等）

SQL标准的方式，如图所示在这里：

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

它是由许多数据库引擎的支持。

Answer 3:

如果你想从查询，而不是PSQL获得它，你可以查询目录模式。这里有一个复杂的查询，做的是：

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
;

这是相当复杂的，但它确实表明你PostgreSQL系统目录中的动力和灵活性，应该让你用自己的方式pg_catalog掌握;-)。请务必在查询中更改了％s的。首先是模式，第二个是表名。

Answer 4:

你可以这样做与psql的斜杠命令：

 \d myTable describe table

这也适用于其他对象：

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

来源： faqs.org

Answer 5:

psql的等效的DESCRIBE TABLE是\d table 。

请参考PostgreSQL手册的PSQL部分的更多细节。

Answer 6:

你可以做一个\d *search pattern * 用星号来查找匹配你感兴趣的搜索模式的表。

Answer 7:

除了命令行\d+ <table_name>您已经发现了，你也可以使用信息架构来查找列数据，使用info_schema.columns

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

Answer 8:

您可以使用此：

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

Answer 9:

使用下面的SQL语句

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

如果更换tbl_name和COL_NAME，它会显示你寻找的特定coloumn的数据类型。

Answer 10:

查询的这种变化（在其他的答案解释）时为我工作。

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

它在这里描述的细节： http://www.postgresqltutorial.com/postgresql-describe-table/

Answer 11:

在MySQL中，DESCRIBE TABLE_NAME

在PostgreSQL，\ d TABLE_NAME

或者，你可以使用这个长的命令：

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 12:

这应该是解决方案：

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

Answer 13:

为了提高对对方的回答的SQL查询（这是伟大的！），这里是一个修改后的查询。它也包括约束名称，继承的信息，并打破了数据类型转换为它的组成部分（类型，长度，精度刻度）。它也过滤掉（在数据库中仍然存在）已经下降了列。

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 14:

您还可以检查使用以下查询

Select * from schema_name.table_name limit 0;

Expmple：我的表有两列名和pwd。给下面的截图。

*使用PG口语陪练

Answer 15:

最好的方式来描述的表，诸如柱，类型，列的改性剂，等等。

\d+ tablename or \d tablename

Answer 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                        |

Answer 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

Answer 18:

/ dt为它列出了你存在的所有数据库中的表的commad。运用
/ d命令和/ d +，我们可以得到一个表的细节。该sysntax会像
* / d TABLE_NAME（或）\ d + TABLE_NAME

Answer 19:

我制定了GET表架构下面的脚本。

'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;

文章来源: PostgreSQL “DESCRIBE TABLE”