From: "myungkyu.lim" <myungkyu.lim@samsung.com>
To: "'Tomas Vondra'" <tomas.vondra@2ndquadrant.com>, "'Adam Berlin'"
	<berlin.ab@gmail.com>, <pgsql-hackers@lists.postgresql.org>
Cc: "'Surafel Temesgen'" <surafel3000@gmail.com>
In-Reply-To: <7f9880a1-416e-649d-3a5a-e36bff538814@2ndquadrant.com>
Subject: RE: COPY FROM WHEN condition
Date: Mon, 12 Nov 2018 16:44:49 +0900
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>> COPY table_name WHERE (some_condition)
>>=20
>> Users should already be familiar with the idea that WHERE performs a fil=
ter.
>>=20

> So, what about using FILTER here? We already use it for aggregates when
> filtering rows to process.

> That being said, I have no strong feelings either way. I'd be OK with
> both WHEN and WHERE.

I don't think it's an important point,

In gram.y,
	where_clause:
			WHERE a_expr							=7B =24=24 =3D =242; =7D
			=7C /*EMPTY*/							=7B =24=24 =3D NULL; =7D
		;
This is similar to the 'opt_when_clause' in this patch.

So, I think 'WHERE' is a better form.

BTW, 3rd patch worked very well in my tests.
However, some wrong code style still exists.

	Node    *whenClause=3D NULL;
	cstate->whenClause=3DwhenClause;

Best regards,
Myungkyu, Lim