Hello,
On Mon, 2022-08-08 at 15:52 +0800, Wind wrote:
> hi~
> I test "tablesample" feature on pg9.5 and found that tablesample
> doesnt support to be applied to subquery.
> for example this sql doesnt work on pg9.5:
> ```
> create table t1(
> c1 int,
> c2 int
> );
> select c2 from (select * from t1) as t2 tablesample system (50);
> ```
> while i read sql2003 standard about tablesample and think it should
> allow this usage according to standard.
> is it a deviation to sql standard?
Version 9.5 is not supported. The oldest supported version is 10, the
current version is 14.
Please read chapter 58 in the doco.
HTH,