我有以下包含重复子查询的巨大查询，它对我来说看起来效率很低。我该如何优化它？
SELECT T2.date1, T2.date2, T2.period, T1.market, T1.ticker, 0 AS scenario
FROM
(SELECT DISTINCT
Q.market AS market,
Q.ticker AS ticker
FROM portfolio.scenario S RIGHT JOIN portfolio.quote Q
ON S.series = (SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1) AND
Q.market = S.market AND
Q.ticker = S.ticker
WHERE Q.date = '2010-07-01' AND
S.date1 IS NULL) AS T1
JOIN
(SELECT DISTINCT S.date1, S.date2, S.period
FROM scenario S
WHERE S.series = (SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1) AND
S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01') AS T2
UNION
SELECT S.date1 AS date1,
S.date2 AS date2,
S.period AS period,
Q.market AS market,
Q.ticker AS ticker,
Q.close * EXP(S.ratio) AS scenario
FROM portfolio.scenario S , portfolio.quote Q
WHERE S.series = (SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1) AND
S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
Q.date = '2010-07-01' AND
Q.market = S.market AND
Q.ticker = S.ticker
UNION
SELECT T2.date1, T2.date2, T2.period, T1.market, T1.ticker, 0 AS scenario
FROM
(SELECT DISTINCT
Q.market AS market,
Q.ticker AS ticker
FROM portfolio.scenario S , portfolio.quote Q
WHERE Q.date = '2010-07-01' AND
Q.market = S.market AND
Q.ticker = S.ticker AND
S.series = (SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1) AND
S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' ) AS T1
JOIN
(SELECT DISTINCT S.date1, S.date2, S.period
FROM scenario S
WHERE S.series = (SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1) AND
S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01') AS T2
WHERE (T2.date1, T2.date2, T2.period, T1.market, T1.ticker)
NOT IN (SELECT S.date1 AS date1,
S.date2 AS date2,
S.period AS period,
Q.market AS market,
Q.ticker AS ticker
FROM portfolio.scenario S , portfolio.quote Q
WHERE Q.date = '2010-07-01' AND
Q.market = S.market AND
Q.ticker = S.ticker AND
S.series = (SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1) AND
S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' )
ORDER BY
date1,date2,period,market,ticker
After @Bruce https://stackoverflow.com/users/99003/bruce-alderson的评论和一些减少子查询的逻辑我现在的查询是：
(SELECT S.date1,
S.date2,
S.period,
Q.market,
Q.ticker,
Q.close * EXP(S.ratio) AS scenario
FROM portfolio.scenario S , portfolio.quote Q
WHERE
S.date1 >= (@date1 := '2009-09-01') AND
S.date2 <= (@date2 := '2010-07-01') AND
Q.date = (@qdate := '2010-07-01') AND
S.series =
(@series :=
(SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1)) AND
Q.market = S.market AND
Q.ticker = S.ticker)
UNION
(SELECT T2.date1, T2.date2, T2.period, T1.market, T1.ticker, 0 AS scenario
FROM
(SELECT Q.market, Q.ticker
FROM quote Q
WHERE Q.date = @qdate) AS T1
JOIN
(SELECT DISTINCT S.date1, S.date2, S.period
FROM scenario S
WHERE S.series = @series AND
S.date1 >= @date1 AND
S.date2 <= @date2) AS T2
WHERE (T2.date1, T2.date2, T2.period, T1.market, T1.ticker)
NOT IN
(SELECT S.date1,
S.date2,
S.period,
Q.market,
Q.ticker
FROM portfolio.scenario S , portfolio.quote Q
WHERE Q.date = @qdate AND
Q.market = S.market AND
Q.ticker = S.ticker AND
S.series = @series AND
S.date1 >= @date1 AND
S.date2 <= @date2 ))
但是，如果我改变了
(@series :=
(SELECT S.series
FROM scenario S
WHERE S.date1 >= '2009-09-01' AND
S.date2 <= '2010-07-01' AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1))
to be
(@series :=
(SELECT S.series
FROM scenario S
WHERE S.date1 >= @date1 AND
S.date2 <= @date2 AND
S.period = 'QUARTER'
ORDER BY S.date2
LIMIT 1))
处理它需要太多时间（我已经执行了10分钟前的查询，但仍然没有得到结果），而查询通常会在5秒内返回。
此外，当我重置变量时，执行结果不正确（可能使用上次执行中的变量值）。我如何在不添加 SET 语句的情况下更改它（我希望它是单个查询）
