Question

如何从Postgres实例中的所有数据库的所有表中查找所有整数类型的主键列及其当前最大值？

我想找到所有表中接近溢出其最大值2147483647的所有int类型主键列。

Answer 1

BEGIN 
   for c in ( select grade, count(*) cnt 
                from gradeReport1
                group by grade
                order by grade ) loop    
     DBMS_OUTPUT.PUT_LINE('There are total ' || c.cnt || ' ' ||c.grade||'s');
   end loop;
END; 
/

然后你可以用

获得一个列表

CREATE OR REPLACE FUNCTION intpkmax() RETURNS
   TABLE(schema_name name, table_name name, column_name name, max_value integer)
   LANGUAGE plpgsql STABLE AS
$$BEGIN
   /* loop through tables with a simgle integer column as primary key */
   FOR schema_name, table_name, column_name IN
      SELECT sch.nspname, tab.relname, col.attname
         FROM pg_class tab
            JOIN pg_constraint con ON con.conrelid = tab.oid
            JOIN pg_attribute col ON col.attrelid = tab.oid
            JOIN pg_namespace sch ON sch.oid = tab.relnamespace
         WHERE con.contype = 'p'
            AND array_length(con.conkey, 1) = 1
            AND col.atttypid = 'integer'::regtype
            AND NOT col.attisdropped
   LOOP
      /* get the maximum value of the primary key column */
      EXECUTE 'SELECT max(' || quote_ident(column_name) ||
              ') FROM ' || quote_ident(schema_name) ||
              '.' || quote_ident(table_name) || ''
         INTO max_value;
      /* return the next result */
      RETURN NEXT;
   END LOOP;
END;$$;

postgres：查找所有具有当前最大值的整数列

1 个答案: