サブクエリから列を取得することに関するいくつかの投稿を見ましたが、それらのほとんどは各列に単一の選択を使用することを提案していますが、これは私の場合です
SELECT CAST(p.idvendor AS VARCHAR(10)), CAST(p.description AS VARCHAR(50)),
(SELECT CAST(NVL(SUM(CASE WHEN locals_sales.cantidad >=0
AND locals_sales.cantidad <locals_sales.pqlocals
THEN 1 ELSE 0 END), '0') AS VARCHAR(10))
FROM locals_sales, agents, vendors, locals, locals_sales, history
WHERE locals.idvendor = vendors.idvendor
AND locals_sales.IDlocals = locals.idlocals
AND agents.codagente=vendors.codagente
AND agents.idagent!=1
AND locals_sales.number_n_line = locals_sales.n_line
AND locals.estado=1
AND vendors.idvendor = p.idvendor
AND history.number_line(+) = locals_sales.n_line
AND history.date(+) >= to_date('4/9/2012 00:00', 'dd/mm/yy HH24:mi:ss')
) AS critic,
(SELECT CAST(NVL(SUM(CASE WHEN locals_sales.cantidad >=locals_sales.pqlocals
AND locals_sales.cantidad <locals_sales.media
THEN 1 ELSE 0 END), '0') AS VARCHAR(10))
FROM locals_sales, agents, vendors, locals, locals_sales, history
WHERE locals.idvendor = vendors.idvendor
AND locals_sales.IDlocals = locals.idlocals
AND agents.codagente=vendors.codagente
AND agents.idagent!=1
AND locals_sales.number_n_line = locals_sales.n_line
AND locals.estado=1
AND vendors.idvendor = p.idvendor
AND history.number_line(+) = locals_sales.n_line
AND history.date(+) >= to_date('4/9/2012 00:00', 'dd/mm/yy HH24:mi:ss')
) AS medium,
(SELECT CAST(NVL(SUM(CASE WHEN locals_sales.cantidad >=locals_sales.media
THEN 1 ELSE 0 END), '0') AS VARCHAR(10))
FROM locals_sales, agents, vendors, locals, locals_sales, history
WHERE locals.idvendor = vendors.idvendor
AND locals_sales.IDlocals = locals.idlocals
AND agents.codagente=vendors.codagente
AND agents.idagent!=1
AND locals_sales.number_n_line = locals_sales.n_line
AND locals.estado=1
AND vendors.idvendor = p.idvendor
AND history.number_line(+) = locals_sales.n_line
AND history.date(+) >= to_date('4/9/2012 00:00', 'dd/mm/yy HH24:mi:ss')
) AS NORMAL
FROM vendors p, agents ag
WHERE ag.codagente=p.codagente
ご覧のとおり、各列に 3 つの SUM があります。これらの列は同じテーブルからのものです。違いは、各選択の各 CASE の前提条件によるものです。
また、各選択のほぼ最後に、これを条件として持っています
vendors.idvendor = p.idvendor
p は、サブクエリの外側のテーブルのエイリアスです
パフォーマンスを向上させるために、ほぼ同様の 3 つの選択を使用せずに、代わりに 3 つの列に対して単一の選択を使用するにはどうすればよいですか?