如何修复此查询?我收到以下错误:
Unknown column 'count_of_confirmed_rec' in 'where clause'
MySQL 查询:
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
最佳答案
首先,用于计算 count_of_confirmed_rec
的子查询与外部查询不相关;因此,它将为查询的所有返回行提供相同的值。不确定这是否是您想要的。
其次,您的条件 d.col_1 = 'value'
看起来也可能不适合左连接。
要测试 where 语句中 count_of_confirmed_rec
的值,您需要将除 WHERE 语句之外的所有内容放入子查询中,并将条件应用于查询返回的行(未经测试):
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
关于mysql - 在 where 子句中使用带有 CASE 的别名列名,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26114161/