Mysql SQL-选择乘法条件
我想使用以下查询选择乘法条件:Mysql SQL-选择乘法条件,mysql,sql,join,database-design,inner-join,Mysql,Sql,Join,Database Design,Inner Join,我想使用以下查询选择乘法条件: SELECT (SELECT count(*) FROM users ) as totalusers, (SELECT sum(cashedout) FROM users ) AS cashedout, (SELECT COUNT(*) FROM xeon_users_rented ) AS totalbots, (SE
SELECT (SELECT count(*)
FROM users
)
as totalusers,
(SELECT sum(cashedout)
FROM users
) AS cashedout,
(SELECT COUNT(*)
FROM xeon_users_rented
) AS totalbots,
(SELECT sum(value)
FROM xeon_stats_clicks
WHERE typ='3' OR typ='1'
) AS totalclicks
执行上述查询只需不到一秒钟(准确地说是0.912秒)。这会大大降低处理数千个请求的速度
对我来说,这种方法似乎合乎逻辑:
SELECT (SELECT count(*), sum(cashedout)
FROM users
)
as totalusers, cashedout,
(SELECT COUNT(*)
FROM xeon_users_rented
) AS totalbots,
(SELECT sum(value)
FROM xeon_stats_clicks
WHERE typ='3' OR typ='1'
) AS totalclicks
但是,这不起作用,因为我得到以下错误:
#1241 - Operand should contain 1 column(s)
此外,在我的第一个查询中,我如何连接另外两个表“
xeon\u users\u rendered
”和“xeon\u stats\u clicks
”?这很慢,因为您有多个子查询。尝试使用联接
此外,您的表、列列表将帮助我们更好地为您提供帮助 您的第二个查询使用了错误的语法,应该是
SELECT
count(*) as totalusers,
sum(cashedout) cashedout,
(SELECT COUNT(*) FROM xeon_users_rented) AS totalbots,
(SELECT sum(value) FROM xeon_stats_clicks
WHERE typ='3' OR typ='1') AS totalclicks
FROM users
发布您的数据库模式、原始数据样本和预期结果更快!但是,我收到一条消息,说在任何列上都没有索引。我应该加一个吗?更重要的是,当我使用“SELECT…AS”
index(typ,value)
时,如何添加索引可能会有所帮助。