[英]Using alias column name with CASE in where clause
如何解決此查詢? 我收到以下錯誤:
“ where子句”中的未知列“ count_of_confirmed_rec”
MySQL查詢:
SELECT
(SELECT COUNT(a.col_1)FROM table_1 a
JOIN table 2 b ON a.col_id= b.col_id) count_of_confirmed_rec,
c.col_1,
FROM table_3 c
LEFT JOIN table_4 d ON c.col_id = d.col_id
WHERE d.col_1 = 'value'
AND c.col_1 = CASE count_of_confirmed_rec
WHEN 0 THEN 0 ELSE 1 END
首先,您用於計算count_of_confirmed_rec
的子查詢與外部查詢不相關; 因此,它將為查詢的所有返回行提供相同的值。 不確定這是否是您想要的。
其次,您的條件d.col_1 = 'value'
對於左聯接也可能放錯了位置。
為了在where語句中測試count_of_confirmed_rec
的值,您需要將WHERE語句以外的所有內容放在子查詢中,並將條件應用於查詢返回的行(未經測試):
select count_of_confirmed_rec, c_col_1 from (
SELECT (SELECT COUNT(a.col_1)FROM table_1 a JOIN table 2 b ON a.col_id= b.col_id) count_of_confirmed_rec, c.col_1 as c_col_1
FROM table_3 c LEFT JOIN table_4 d ON c.col_id = d.col_id
WHERE d.col_1 = 'value'
) SQ
where c_col_1 = CASE count_of_confirmed_rec WHEN 0 THEN 0 ELSE 1 END
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.