[英]Use Select data in nested Select statement in MySQL
I have a query in MySQL.我在 MySQL 中有一个查询。
Full Query完整查询
SELECT
tc.expense AS expense,
tc.tour_sub_code,
tc.login_id
FROM
tc_wallet tc
WHERE tc.login_id = 'vinod.kumbala'
AND tc.expense = 'Daily Allowance'
AND tc.delete_flag = 'F'
AND tc.status != 'reject'
Result结果
Expense Tour_sub_code login_id
DAILY ALLOWANCE MOS-EUROPE100119 vinod.kumbala
DAILY ALLOWANCE Test vinod.kumbala
Initially I am fetching data from tc_wallet
table.最初我从
tc_wallet
表中获取数据。
Now my requirement is that I need to find the total count of attendances for a particular tour_sub_code
.现在我的要求是我需要找到特定
tour_sub_code
的总出席人数。 Attendances count can be found from attendance_master
table for that particular tour_sub_code
.出勤次数可以从
attendance_master
该特定tour_sub_code
attendance_master
表中tour_sub_code
。 So I included a nested select query which is所以我包含了一个嵌套的选择查询,它是
Nested select嵌套选择
(SELECT
COUNT(*)
FROM
(SELECT
*
FROM
`attendance_master`
WHERE `delete_flag` = 'F'
AND login_id = 'vinod.kumbala'
AND `tour_sub_code` = tc.`tour_sub_code`
GROUP BY `device_date`) t1) AS newNoOfdays
Full Query完整查询
SELECT
tc.expense AS expense,
tc.tour_sub_code,
tc.login_id,
(SELECT
COUNT(*)
FROM
(SELECT
*
FROM
`attendance_master`
WHERE `delete_flag` = 'F'
AND login_id = 'vinod.kumbala'
AND `tour_sub_code` = tc.`tour_sub_code`
GROUP BY `device_date`) t1) AS newNoOfdays
FROM
tc_wallet tc
WHERE tc.login_id = 'vinod.kumbala'
AND tc.expense = 'Daily Allowance'
AND tc.delete_flag = 'F'
AND tc.status != 'reject'
Now this query gives me error as现在这个查询给了我错误
Unknown column 'tc.tour_sub_code' in 'where clause'“where 子句”中的未知列“tc.tour_sub_code”
Expected Result预期结果
Expense Tour_sub_code login_id Count
DAILY ALLOWANCE MOS-EUROPE100119 vinod.kumbala 20
DAILY ALLOWANCE Test vinod.kumbala 44
Can I know where I am going wrong with this ?我能知道我哪里出错了吗?
Also is there any other way i get result like by using JOINS ?还有其他方法可以通过使用 JOINS 获得结果吗?
In the innermost subquery you are referencing a column from the outer most query.在最内层的子查询中,您引用的是最外层查询中的一列。 This is not permitted for subqueries in the FROM clause (derived tables).
这对于 FROM 子句(派生表)中的子查询是不允许的。 However - You don't need that subquery.
但是 - 您不需要该子查询。 What you need is
COUNT(DISTINCT device_date)
你需要的是
COUNT(DISTINCT device_date)
Rewrite改写
(SELECT
COUNT(*)
FROM
(SELECT
*
FROM
`attendance_master`
WHERE `delete_flag` = 'F'
AND login_id = 'vinod.kumbala'
AND `tour_sub_code` = tc.`tour_sub_code`
GROUP BY `device_date`) t1) AS newNoOfdays
to到
(SELECT
COUNT(DISTINCT device_date)
FROM `attendance_master`
WHERE `delete_flag` = 'F'
AND login_id = 'vinod.kumbala'
AND `tour_sub_code` = tc.`tour_sub_code`
) AS newNoOfdays
You can also rewrite the full query to a LEFT JOIN query:您还可以将完整查询重写为 LEFT JOIN 查询:
SELECT
tc.expense AS expense,
tc.tour_sub_code,
tc.login_id,
COUNT(DISTINCT device_date) AS newNoOfdays
FROM tc_wallet tc
LEFT JOIN attendance_master am
ON am.tour_sub_code = tc.tour_sub_code
AND am.delete_flag = 'F'
AND am.login_id = 'vinod.kumbala'
WHERE tc.login_id = 'vinod.kumbala'
AND tc.expense = 'Daily Allowance'
AND tc.delete_flag = 'F'
AND tc.status != 'reject'
Try this:尝试这个:
SELECT
tc.expense AS expense,
tc.tour_sub_code,
tc.login_id,
count(*) as count
FROM
tc_wallet tc
INNER JOIN
attendance_master am
ON
tc.tour_sub_code = am.tour_sub_code AND
tc.login_id = am.login_id
WHERE tc.login_id = 'vinod.kumbala'
AND tc.expense = 'Daily Allowance'
AND tc.delete_flag = 'F'
AND tc.status != 'reject'
GROUP BY
tc.expense AS expense,
tc.tour_sub_code,
tc.login_id
Try This ---尝试这个 - -
SELECT
tc.expense AS expense,
tc.tour_sub_code,
tc.login_id,
(SELECT
COUNT(am.*)
FROM `attendance_master` as am
WHERE am.delete_flag = 'F'
AND am.login_id = 'vinod.kumbala'
AND am.tour_sub_code = tc.tour_sub_code
GROUP BY am.device_date) AS count
FROM
tc_wallet tc
WHERE tc.login_id = 'vinod.kumbala'
AND tc.expense = 'Daily Allowance'
AND tc.delete_flag = 'F'
AND tc.status != 'reject'
Can you try this:你能试试这个吗:
select tc.expense AS expense,
tc.tour_sub_code,
tc.login_id,
newNoOfdays.countVal
from tc_wallet tc
inner join
( select tour_sub_code, count('A') 'countval'
from attendance_master ascs (nolock)
group by tour_sub_code) as newNoOfdays
on newNoOfdays.tour_sub_code = tc.tour_sub_code
where tc.login_id = 'vinod.kumbala'
AND tc.expense = 'Daily Allowance'
AND tc.delete_flag = 'F'
AND tc.status != 'reject'
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