SUM(CASE WHEN t2.月份 = '01' THEN t2.数量 END) AS 一月用法

在查询中，`SUM(CASE WHEN t2.月份 = '01' THEN t2.数量 END)` 是使用了条件聚合函数（CASE WHEN）和 SUM 函数来计算一月份的数量总和。

这个表达式的含义是，当 t2.月份 等于 '01' 时，返回 t2.数量 的值，否则返回 NULL。然后，使用 SUM 函数对这些非 NULL 值进行求和，得到一月份的总和。

在整个查询结果中，这个表达式将被命名为 "一月"，并显示一月份的数量总和。

你可以根据需要在查询中使用类似的表达式来计算其他月份的数量总和。只需将条件 `t2.月份 = '01'` 更改为相应的月份条件即可。例如，要计算二月份的数量总和，可以使用 `SUM(CASE WHEN t2.月份 = '02' THEN t2.数量 END)`。

请注意，条件聚合函数（CASE WHEN）结合 SUM 函数可以用于根据特定条件对数据进行聚合计算。通过更改条件，你可以根据不同的情况计算不同的汇总值。

相关问题

select t1.month_id, count(distinct case when t1.offer_type_name='主套餐' then offer_name end) aa, count(distinct case when t1.offer_type_name='促销' then offer_name end) bb, count(distinct case when t1.offer_type_name='可选包' then offer_name end) cc, count(distinct case when t2.offer_type_name='主套餐' then offer_name end) aaa, count(distinct case when t2.offer_type_name='促销' then offer_name end) bbb, count(distinct case when t2.offer_type_name='可选包' then offer_name end) ccc, from zone_crmchk.dwd_sum_zhuliuxxsc t1 left join zone_crmchk.dwd_sum_zhuliuxxsc t2 on t2.month < t1.month group by t1.month, count(distinct case when offer_type_name='主套餐' then offer_name end) aa, count(distinct case when offer_type_name='促销' then offer_name end) bb, count(distinct case when offer_type_name='可选包' then offer_name end) cc

根据您提供的 SQL 查询语句，我发现其中存在一个逗号(,)出现在了 FROM 子句之后，这是一个语法错误。您需要将逗号(,)删除，同时将查询语句修改为如下形式：

SELECT
    t1.month_id, 
    COUNT(DISTINCT CASE WHEN t1.offer_type_name='主套餐' THEN offer_name END) aa, 
    COUNT(DISTINCT CASE WHEN t1.offer_type_name='促销' THEN offer_name END) bb, 
    COUNT(DISTINCT CASE WHEN t1.offer_type_name='可选包' THEN offer_name END) cc, 
    COUNT(DISTINCT CASE WHEN t2.offer_type_name='主套餐' THEN offer_name END) aaa, 
    COUNT(DISTINCT CASE WHEN t2.offer_type_name='促销' THEN offer_name END) bbb, 
    COUNT(DISTINCT CASE WHEN t2.offer_type_name='可选包' THEN offer_name END) ccc
FROM 
    zone_crmchk.dwd_sum_zhuliuxxsc t1 
    LEFT JOIN zone_crmchk.dwd_sum_zhuliuxxsc t2 ON t2.month < t1.month 
GROUP BY 
    t1.month_id, 
    COUNT(DISTINCT CASE WHEN offer_type_name='主套餐' THEN offer_name END), 
    COUNT(DISTINCT CASE WHEN offer_type_name='促销' THEN offer_name END), 
    COUNT(DISTINCT CASE WHEN offer_type_name='可选包' THEN offer_name END);

这样修改后，查询语句应该就能正确执行了。

优化这条sql： select distinct (select product_name from t_product from where id = #{productId} and mark = 1 and status = 1) as productName, (select count(0) from t_clue a where a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId} and a.status in(1,2,3,31,32,33)) as clueCount, (select count(0) from t_clue a left join t_clue_appendix b on a.clue_code = b.clue_code where a.distribution_status != 4 and a.mark = 1 and b.file_url is not null and a.product_id = #{productId} and a.status in (3,31,32,33)) as intentionCount, (select count(0) from t_clue a where a.status in (4,5,7,8) and a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId} and a.status = 4) as incomingCount, (select count(0) from t_clue a where a.status in (5,7,8) and a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId} and a.status in (5,7,8)) as approvedCount, (select count(0) from t_clue a where a.status = 6 and a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId} and a.status = 6) as rejectionCount, (select count(0) from t_clue a where a.status in (7,8) and a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId}) as loanCount, (select count(0) from t_clue a where a.status = 8 and a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId}) as swipeCount, (select sum(a.loan_amount) from t_clue a where a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId}) as loanMoney, (select sum(a.use_amount) from t_clue a where a.distribution_status != 4 and a.mark = 1 and a.product_id = #{productId}) as swipeMoney

可以考虑使用 JOIN 语句替换子查询，同时对查询中的字段添加索引以提高查询效率。修改后的 SQL 可能如下所示：

SELECT 
    t1.product_name AS productName,
    COUNT(CASE WHEN t2.status IN (1,2,3,31,32,33) THEN 1 END) AS clueCount,
    COUNT(CASE WHEN t2.status IN (3,31,32,33) AND t3.file_url IS NOT NULL THEN 1 END) AS intentionCount,
    COUNT(CASE WHEN t2.status = 4 THEN 1 END) AS incomingCount,
    COUNT(CASE WHEN t2.status IN (5,7,8) THEN 1 END) AS approvedCount,
    COUNT(CASE WHEN t2.status = 6 THEN 1 END) AS rejectionCount,
    COUNT(CASE WHEN t2.status IN (7,8) THEN 1 END) AS loanCount,
    COUNT(CASE WHEN t2.status = 8 THEN 1 END) AS swipeCount,
    SUM(t2.loan_amount) AS loanMoney,
    SUM(t2.use_amount) AS swipeMoney
FROM 
    t_product t1
    JOIN t_clue t2 ON t1.id = t2.product_id
    LEFT JOIN t_clue_appendix t3 ON t2.clue_code = t3.clue_code
WHERE 
    t1.id = #{productId} AND t1.mark = 1 AND t1.status = 1 AND t2.distribution_status != 4 AND t2.mark = 1
GROUP BY 
    t1.product_name;