pgsql高阶用法

字符串转64位整数：

drop function hex_to_bigint(text);
CREATE FUNCTION
hex_to_bigint(in_hex TEXT)
RETURNS BIGINT
IMMUTABLE STRICT LANGUAGE sql AS
$body$
  SELECT CAST(CAST(('x' || CAST($1 AS text)) AS bit(64)) AS BIGINT);
$body$;