Postgresql type casting information using pg_cast

Query to Postgresql type casting information:

SELECT ct.*,
source_t.typname as source_type
,target_t.typname as target_type
, proc.proname
FROM
pg_cast as ct
, pg_type as source_t
, pg_type as target_t
,pg_proc as proc
WHERE
ct.castsource = source_t.oid
and ct.casttarget = target_t.oid
and  ct.castfunc =  proc.oid

  source_type  |  target_type  |   proname   | castcontext | castmethod
---------------+---------------+-------------+-------------+------------
 int8          | int2          | int2        | a           | f
 int8          | int4          | int4        | a           | f
 int8          | float4        | float4      | i           | f
 int8          | float8        | float8      | i           | f
 int8          | numeric       | numeric     | i           | f
 int2          | int8          | int8        | i           | f
 int2          | int4          | int4        | i           | f
 int2          | float4        | float4      | i           | f
 int2          | float8        | float8      | i           | f
 int2          | numeric       | numeric     | i           | f
 int4          | int8          | int8        | i           | f

...
(143 rows)

The details of pg_cast is available at
http://www.postgresql.org/docs/9.2/static/catalog-pg-cast.html

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