how to make short time for select

[andre gunawan]

how to make short time when i'm doing select rows with many tables for selected (there are concate and substring)
in example:

SELECT dpo.tanggal, dpo.bukti, dpo.qtyminta, dpo.qtybeli, dpo.nosppb, nomorsppb, tpo.supplier, tpo.nopo, CASE WHEN (tpo.supplier = 'CASH') THEN sup.supplier ELSE sup.nama END AS namasupp, CONCAT(dpo.bukti,'-', SUBSTRING(dpo.nosppb, 3, 4), '/', LEFT(dpo.nosppb, 2), '/',RIGHT(dpo.periode, 4)) as npo FROM dtlpo dpo, trnpo tpo, supplier sup WHERE tpo.bukti = dpo.bukti AND tpo.periode = dpo.periode and sup.supplier = tpo.supplier

in my case there are 40029 rows selected...