PG庫查詢表結構，字段名，長度，主鍵（支持多主鍵），備註等信息

網上找了一圈也沒有一個支持多主鍵查詢的，自己參考資料寫了一個，可以查詢字段名，類型，長度，主鍵（支持多主鍵），備註等信息

select a.attnum,
       a.attname                                                 columnName,
       t.typname                                                 columnType,
       coalesce(d.character_maximum_length, d.numeric_precision) columnLength,
       d.numeric_scale                                           numericScaleLength,
       (a.attnotnull is false)                                   isNullable,
       d.column_default                                          defaultValue,
       col_description(a.attrelid, a.attnum) as                  columnComment,
       case when length(b.attname) > 0 then 'PRI' end as columnKey
from pg_class c,
     pg_attribute a,
     pg_type t,
     information_schema.columns d
left join (
    select pg_attribute.attname
    from pg_index,
         pg_class,
         pg_attribute
    where pg_class.oid = '表名' :: regclass
      and pg_index.indrelid = pg_class.oid
      and pg_attribute.attrelid = pg_class.oid
      and pg_attribute.attnum = any (pg_index.indkey)
) b on d.column_name = b.attname
where a.attrelid = c.oid
  and a.atttypid = t.oid
  and a.attnum > 0
  and c.relname = d.table_name
  and d.column_name = a.attname
  and c.relname = '表名';