1、查询主键名称

SELECT

       pg_constraint.conname AS pk_name

FROM

       pg_constraint

INNER JOIN pg_class on pg_constraint.conrelied = pg_class.oid

WHERE

pg_class.realname ='table_name'

AND pg_constraint.con type = 'p'

2、查询主键的详细信息

SELECT

       pg_constraint.conname AS pk_name,

      pg_attribute.attname AS colname,

     pg_type.typname AS typename

FROM

       pg_constraint

INNER JOIN pg_class on pg_constraint.conrelied = pg_class.oid

INNER JOIN pg_attribute.attreid=pg_class.oid

AND pg_attribute.attnum = pg_constraint.conkey[1]

INNER JOIN pg_type ON pg_type.oid=pg_attribute.atttypid

WHERE

pg_class.realname ='table_name'

AND pg_constraint.con type = 'p'