[英]Use Select data in nested Select statement in MySQL
我在 MySQL 中有一個查詢。
完整查詢
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'
結果
Expense Tour_sub_code login_id
DAILY ALLOWANCE MOS-EUROPE100119 vinod.kumbala
DAILY ALLOWANCE Test vinod.kumbala
最初我從tc_wallet
表中獲取數據。
現在我的要求是我需要找到特定tour_sub_code
的總出席人數。 出勤次數可以從attendance_master
該特定tour_sub_code
attendance_master
表中tour_sub_code
。 所以我包含了一個嵌套的選擇查詢,它是
嵌套選擇
(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
完整查詢
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'
現在這個查詢給了我錯誤
“where 子句”中的未知列“tc.tour_sub_code”
預期結果
Expense Tour_sub_code login_id Count
DAILY ALLOWANCE MOS-EUROPE100119 vinod.kumbala 20
DAILY ALLOWANCE Test vinod.kumbala 44
我能知道我哪里出錯了嗎?
還有其他方法可以通過使用 JOINS 獲得結果嗎?
在最內層的子查詢中,您引用的是最外層查詢中的一列。 這對於 FROM 子句(派生表)中的子查詢是不允許的。 但是 - 您不需要該子查詢。 你需要的是COUNT(DISTINCT device_date)
改寫
(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
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
您還可以將完整查詢重寫為 LEFT JOIN 查詢:
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'
嘗試這個:
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
嘗試這個 - -
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'
你能試試這個嗎:
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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