在PostgreSQL中列出带索引的列

我想在PostgreSQL中获得索引上的列。

在MySQL中，您可以使用SHOW INDEXES FOR表并查看Column_name列。

mysql> show indexes from foos;

+-------+------------+---------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name            | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------+------------+---------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| foos  |          0 | PRIMARY             |            1 | id          | A         |       19710 |     NULL | NULL   |      | BTREE      |         | 
| foos  |          0 | index_foos_on_email |            1 | email       | A         |       19710 |     NULL | NULL   | YES  | BTREE      |         | 
| foos  |          1 | index_foos_on_name  |            1 | name        | A         |       19710 |     NULL | NULL   |      | BTREE      |         | 
+-------+------------+---------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+

PostgreSQL中存在类似的东西吗?

我已经在psql命令提示符中尝试了\d(使用-E选项来显示SQL)，但它没有显示我正在寻找的信息。

更新:感谢大家的回答。cope360提供了我想要的东西，但也有一些人提供了非常有用的链接。为了将来的参考，请查看pg_index的文档(通过Milen A. Radev)和非常有用的文章从PostgreSQL提取META信息(通过micharov Niklas)。

当前回答

一些样本数据…

create table test (a int, b int, c int, constraint pk_test primary key(a, b));
create table test2 (a int, b int, c int, constraint uk_test2 unique (b, c));
create table test3 (a int, b int, c int, constraint uk_test3b unique (b), constraint uk_test3c unique (c), constraint uk_test3ab unique (a, b));

使用pg_get_indexdef函数:

select pg_get_indexdef(indexrelid) from pg_index where indrelid = 'test'::regclass;

                    pg_get_indexdef
--------------------------------------------------------
 CREATE UNIQUE INDEX pk_test ON test USING btree (a, b)
(1 row)


select pg_get_indexdef(indexrelid) from pg_index where indrelid = 'test2'::regclass;
                     pg_get_indexdef
----------------------------------------------------------
 CREATE UNIQUE INDEX uk_test2 ON test2 USING btree (b, c)
(1 row)


select pg_get_indexdef(indexrelid) from pg_index where indrelid ='test3'::regclass;
                      pg_get_indexdef
------------------------------------------------------------
 CREATE UNIQUE INDEX uk_test3b ON test3 USING btree (b)
 CREATE UNIQUE INDEX uk_test3c ON test3 USING btree (c)
 CREATE UNIQUE INDEX uk_test3ab ON test3 USING btree (a, b)
(3 rows)

2010-02-06 00:09:47

其他回答

@cope360的精彩回答，转换为使用连接语法。

select t.relname as table_name
     , i.relname as index_name
     , array_to_string(array_agg(a.attname), ', ') as column_names
from pg_class t
join pg_index ix
on t.oid = ix.indrelid
join pg_class i
on i.oid = ix.indexrelid
join pg_attribute a
on a.attrelid = t.oid
and a.attnum = ANY(ix.indkey)
where t.relkind = 'r'
and t.relname like 'test%'
group by t.relname
       , i.relname
order by t.relname
       , i.relname
;

2016-11-11 18:00:07

创建一些测试数据…

create table test (a int, b int, c int, constraint pk_test primary key(a, b));
create table test2 (a int, b int, c int, constraint uk_test2 unique (b, c));
create table test3 (a int, b int, c int, constraint uk_test3b unique (b), constraint uk_test3c unique (c),constraint uk_test3ab unique (a, b));

列出索引的索引和列:

select
    t.relname as table_name,
    i.relname as index_name,
    a.attname as column_name
from
    pg_class t,
    pg_class i,
    pg_index ix,
    pg_attribute a
where
    t.oid = ix.indrelid
    and i.oid = ix.indexrelid
    and a.attrelid = t.oid
    and a.attnum = ANY(ix.indkey)
    and t.relkind = 'r'
    and t.relname like 'test%'
order by
    t.relname,
    i.relname;

 table_name | index_name | column_name
------------+------------+-------------
 test       | pk_test    | a
 test       | pk_test    | b
 test2      | uk_test2   | b
 test2      | uk_test2   | c
 test3      | uk_test3ab | a
 test3      | uk_test3ab | b
 test3      | uk_test3b  | b
 test3      | uk_test3c  | c

卷起列名:

select
    t.relname as table_name,
    i.relname as index_name,
    array_to_string(array_agg(a.attname), ', ') as column_names
from
    pg_class t,
    pg_class i,
    pg_index ix,
    pg_attribute a
where
    t.oid = ix.indrelid
    and i.oid = ix.indexrelid
    and a.attrelid = t.oid
    and a.attnum = ANY(ix.indkey)
    and t.relkind = 'r'
    and t.relname like 'test%'
group by
    t.relname,
    i.relname
order by
    t.relname,
    i.relname;

 table_name | index_name | column_names
------------+------------+--------------
 test       | pk_test    | a, b
 test2      | uk_test2   | b, c
 test3      | uk_test3ab | a, b
 test3      | uk_test3b  | b
 test3      | uk_test3c  | c

2010-02-06 13:17:34

\d table_name显示了来自psql的这些信息，但是如果你想使用SQL从数据库中获取这些信息，那么可以看看从PostgreSQL中提取META信息。

我在我的实用程序中使用这些信息来报告来自db schema的一些信息，以比较测试和生产环境中的PostgreSQL数据库。

2010-02-05 07:03:58

一些样本数据…

create table test (a int, b int, c int, constraint pk_test primary key(a, b));
create table test2 (a int, b int, c int, constraint uk_test2 unique (b, c));
create table test3 (a int, b int, c int, constraint uk_test3b unique (b), constraint uk_test3c unique (c), constraint uk_test3ab unique (a, b));

使用pg_get_indexdef函数:

select pg_get_indexdef(indexrelid) from pg_index where indrelid = 'test'::regclass;

                    pg_get_indexdef
--------------------------------------------------------
 CREATE UNIQUE INDEX pk_test ON test USING btree (a, b)
(1 row)


select pg_get_indexdef(indexrelid) from pg_index where indrelid = 'test2'::regclass;
                     pg_get_indexdef
----------------------------------------------------------
 CREATE UNIQUE INDEX uk_test2 ON test2 USING btree (b, c)
(1 row)


select pg_get_indexdef(indexrelid) from pg_index where indrelid ='test3'::regclass;
                      pg_get_indexdef
------------------------------------------------------------
 CREATE UNIQUE INDEX uk_test3b ON test3 USING btree (b)
 CREATE UNIQUE INDEX uk_test3c ON test3 USING btree (c)
 CREATE UNIQUE INDEX uk_test3ab ON test3 USING btree (a, b)
(3 rows)

2010-02-06 00:09:47

下面是一个包装cope360答案的函数:

CREATE OR REPLACE FUNCTION getIndices(_table_name varchar)
  RETURNS TABLE(table_name varchar, index_name varchar, column_name varchar) AS $$
  BEGIN
    RETURN QUERY
    select
    t.relname::varchar as table_name,
    i.relname::varchar as index_name,
    a.attname::varchar as column_name
from
    pg_class t,
    pg_class i,
    pg_index ix,
    pg_attribute a
where
    t.oid = ix.indrelid
    and i.oid = ix.indexrelid
    and a.attrelid = t.oid
    and a.attnum = ANY(ix.indkey)
    and t.relkind = 'r'
    and t.relname = _table_name
order by
    t.relname,
    i.relname;
  END;
  $$ LANGUAGE plpgsql;

用法:

select * from getIndices('<my_table>')

2016-11-12 09:45:53

在PostgreSQL中列出带索引的列

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