SELECT conrelid::regclass AS table_name, 
       conname AS foreign_key, 
       pg_get_constraintdef(oid) 
FROM   pg_constraint 
WHERE  contype = 'f' 
AND    connamespace = 'public'::regnamespace   
ORDER  BY conrelid::regclass::text, contype DESC;

https://soft-builder.com/how-to-list-all-foreign-keys-in-postgresql-database

最快的验证直接在bash答案完全基于这个答案

IFS='' read -r -d '' sql_code << EOF_SQL_CODE
      SELECT
      o.oid
      , o.conname AS constraint_name
      , (SELECT nspname FROM pg_namespace WHERE oid=m.relnamespace) AS source_schema
      , m.relname AS source_table
      , (SELECT a.attname FROM pg_attribute a
      WHERE a.attrelid = m.oid AND a.attnum = o.conkey[1] AND a.attisdropped = false) AS source_column
      , (SELECT nspname FROM pg_namespace
      WHERE oid=f.relnamespace) AS target_schema
      , f.relname AS target_table
      , (SELECT a.attname FROM pg_attribute a
      WHERE a.attrelid = f.oid AND a.attnum = o.confkey[1] AND a.attisdropped = false) AS target_column
      , ROW_NUMBER () OVER (ORDER BY o.oid) as rowid
      FROM pg_constraint o
      LEFT JOIN pg_class f ON f.oid = o.confrelid
      LEFT JOIN pg_class m ON m.oid = o.conrelid
      WHERE 1=1
      AND o.contype = 'f'
      AND o.conrelid IN (SELECT oid FROM pg_class c WHERE c.relkind = 'r')
EOF_SQL_CODE

psql -d my_db -c "$sql_code"

SELECT conrelid::regclass AS table_name, 
       conname AS foreign_key, 
       pg_get_constraintdef(oid) 
FROM   pg_constraint 
WHERE  contype = 'f' 
AND    connamespace = 'public'::regnamespace   
ORDER  BY conrelid::regclass::text, contype DESC;

https://soft-builder.com/how-to-list-all-foreign-keys-in-postgresql-database

Ollyc的答案很好，因为它不是特定于postgres的，但是，当外键引用多个列时，它就会崩溃。以下查询适用于任意数量的列，但它严重依赖于Postgres扩展:

select 
    att2.attname as "child_column", 
    cl.relname as "parent_table", 
    att.attname as "parent_column",
    conname
from
   (select 
        unnest(con1.conkey) as "parent", 
        unnest(con1.confkey) as "child", 
        con1.confrelid, 
        con1.conrelid,
        con1.conname
    from 
        pg_class cl
        join pg_namespace ns on cl.relnamespace = ns.oid
        join pg_constraint con1 on con1.conrelid = cl.oid
    where
        cl.relname = 'child_table'
        and ns.nspname = 'child_schema'
        and con1.contype = 'f'
   ) con
   join pg_attribute att on
       att.attrelid = con.confrelid and att.attnum = con.child
   join pg_class cl on
       cl.oid = con.confrelid
   join pg_attribute att2 on
       att2.attrelid = con.conrelid and att2.attnum = con.parent

正确的解决方案，使用information_schema，使用多列键，在两个表中正确地连接不同名称的列，并且与ms sqlsever兼容:

select fks.TABLE_NAME as foreign_key_table_name
, fks.CONSTRAINT_NAME as foreign_key_constraint_name
, kcu_foreign.COLUMN_NAME as foreign_key_column_name
, rc.UNIQUE_CONSTRAINT_NAME as primary_key_constraint_name
, pks.TABLE_NAME as primary_key_table_name
, kcu_primary.COLUMN_NAME as primary_key_column_name
from INFORMATION_SCHEMA.TABLE_CONSTRAINTS fks -- foreign keys
inner join INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu_foreign -- the columns of the above keys
    on fks.TABLE_CATALOG = kcu_foreign.TABLE_CATALOG
    and fks.TABLE_SCHEMA = kcu_foreign.TABLE_SCHEMA
    and fks.TABLE_NAME = kcu_foreign.TABLE_NAME
    and fks.CONSTRAINT_NAME = kcu_foreign.CONSTRAINT_NAME
inner join INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc -- referenced constraints
    on rc.CONSTRAINT_CATALOG = fks.CONSTRAINT_CATALOG
    and rc.CONSTRAINT_SCHEMA = fks.CONSTRAINT_SCHEMA
    and rc.CONSTRAINT_NAME = fks.CONSTRAINT_NAME
inner join INFORMATION_SCHEMA.TABLE_CONSTRAINTS pks -- primary keys (referenced by fks)
    on rc.UNIQUE_CONSTRAINT_CATALOG = pks.CONSTRAINT_CATALOG
    and rc.UNIQUE_CONSTRAINT_SCHEMA = pks.CONSTRAINT_SCHEMA
    and rc.UNIQUE_CONSTRAINT_NAME = pks.CONSTRAINT_NAME
inner join INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu_primary
    on pks.TABLE_CATALOG = kcu_primary.TABLE_CATALOG
    and pks.TABLE_SCHEMA = kcu_primary.TABLE_SCHEMA
    and pks.TABLE_NAME = kcu_primary.TABLE_NAME
    and pks.CONSTRAINT_NAME = kcu_primary.CONSTRAINT_NAME
    and kcu_foreign.ORDINAL_POSITION = kcu_primary.ORDINAL_POSITION -- this joins the columns
where fks.TABLE_SCHEMA = 'dbo' -- replace with schema name
and fks.TABLE_NAME = 'your_table_name' -- replace with table name
and fks.CONSTRAINT_TYPE = 'FOREIGN KEY'
and pks.CONSTRAINT_TYPE = 'PRIMARY KEY'
order by fks.constraint_name, kcu_foreign.ORDINAL_POSITION

注意:在potgresql和sqlserver的information_schema实现之间存在一些差异，这使得顶部答案在两个系统上给出不同的结果——一个显示外键表的列名，另一个显示主键表的列名。出于这个原因，我决定使用KEY_COLUMN_USAGE视图。

扩展到ollyc配方:

CREATE VIEW foreign_keys_view AS
SELECT
    tc.table_name, kcu.column_name,
    ccu.table_name AS foreign_table_name,
    ccu.column_name AS foreign_column_name
FROM
    information_schema.table_constraints AS tc
    JOIN information_schema.key_column_usage 
        AS kcu ON tc.constraint_name = kcu.constraint_name
    JOIN information_schema.constraint_column_usage 
        AS ccu ON ccu.constraint_name = tc.constraint_name
WHERE constraint_type = 'FOREIGN KEY';

然后:

SELECT * FROM foreign_keys_view WHERE table_name='YourTableNameHere';