如何在表格上选择并计算出现的一些值

Question

我向你寻求帮助是因为我不太了解 SQL。

我需要从表列中计算一些值的出现次数，以达到如下图所示的统计表效果：

需要的结果：

评论：

我的结果表需要有前两列（contry 和 site）来自第一个表“Violations”，接下来的 5 列将包含每个可能的 id 值中“Violations”中 status_id 出现次数（计数）状态表。

解释：

所以，我有两个表：Violations 和 Status。请看我的sqlfiddle

违规：

• id 长，
• 国家/地区 varchar(20),
• 站点 varchar(20),
• status_id long,
• ...在这种情况下其他不重要的列

状态：

• id 长，
• 状态长 “状态”列的值 (1-4) 映射到字符串值：疑似违规 (1)、确认违规 (2)、确认无违规 (3)、未确定 (4)

在我的加入（或仅基于一个表违规）的结果中，表应该包含列：

• 来自违规表：“国家/地区”和“网站”
• 来自状态表：“怀疑违规”、“确认违规”、“确认无违规”、“未确定”、“总计”（其中此列是违规表中出现的计数器）。

当前状态和新要求：

第一次尝试在下面完成（感谢 bluefeet），几乎完美......

select v.country,
v.site,
    SUM(case when s.id = 1 then 1 else 0 end) Total_SuspectedViolations,
    SUM(case when s.id = 2 then 1 else 0 end) Total_ConfirmedViolations,
    SUM(case when s.id = 3 then 1 else 0 end) Total_ConfirmedNoViolations,
    SUM(case when s.id = 4 then 1 else 0 end) Total_NotDetermined,
    COUNT(*) Total
from violations v
inner join status s
    on v.status_id = s.id
group by v.country, v.site

或不加入：

select v.country,
v.site,
    SUM(case when v.status_id = 1 then 1 else 0 end) Total_SuspectedViolations,
    SUM(case when v.status_id = 2 then 1 else 0 end) Total_ConfirmedViolations,
    SUM(case when v.status_id = 3 then 1 else 0 end) Total_ConfirmedNoViolations,
    SUM(case when v.status_id = 4 then 1 else 0 end) Total_NotDetermined,
    COUNT(*) Total
from violations v
group by v.country, v.site

...但不包括您在图片中看到的 3 个问题。我的意思是：

• “-全部-”应该计算所有国家/地区的出现次数
• "- Unknown -" 应该计算某些未识别国家/地区的出现次数
• “- 全部 -”（针对每个国家/地区）- 应计算一个国家/地区内的出现次数

补充说明：

• -Unknown-含义：

Unknown 应该计算例如在 DB Country 表中不存在或名称/ID 错误的国家/地区的出现次数，这就是为什么这里将其视为 Unknown（我忘了提到 DB 中有表 Country） . 站点也是如此，站点的Unknown 意味着有人在 Violations.status_id 中输入了错误的值，而不是在范围 (1-4) 中，因为这些只是状态表中存在的可接受值。

• 我们可以假设表 Country 如下所示：

国家：

• id 长，
• 名称 varchar(30)

请帮助我编写包含这 3 个条件的正确 sql 查询，因为我有一个大问题要做。

Answer 1

All 可以使用UNION 语句轻松完成（结果见sqlFiddle）：

(SELECT v.country,
    v.site,
    SUM(CASE WHEN v.status_id = 1 THEN 1 ELSE 0 END) Total_SuspectedViolations,
    SUM(CASE WHEN v.status_id = 2 THEN 1 ELSE 0 END) Total_ConfirmedViolations,
    SUM(CASE WHEN v.status_id = 3 THEN 1 ELSE 0 END) Total_ConfirmedNoViolations,
    SUM(CASE WHEN v.status_id = 4 THEN 1 ELSE 0 END) Total_NotDetermined,
    COUNT(*) Total,
    0  'isAll'
FROM violations v
GROUP BY v.country, v.site)
union(
SELECT v.country,
    '- All -',
    SUM(CASE WHEN v.status_id = 1 THEN 1 ELSE 0 END) Total_SuspectedViolations,
    SUM(CASE WHEN v.status_id = 2 THEN 1 ELSE 0 END) Total_ConfirmedViolations,
    SUM(CASE WHEN v.status_id = 3 THEN 1 ELSE 0 END) Total_ConfirmedNoViolations,
    SUM(CASE WHEN v.status_id = 4 THEN 1 ELSE 0 END) Total_NotDetermined,
    COUNT(*) Total,
  1  'isAll'
FROM violations v
GROUP BY v.country)
UNION (
SELECT '- All -',
    '- All -',
    SUM(CASE WHEN v.status_id = 1 THEN 1 ELSE 0 END) Total_SuspectedViolations,
    SUM(CASE WHEN v.status_id = 2 THEN 1 ELSE 0 END) Total_ConfirmedViolations,
    SUM(CASE WHEN v.status_id = 3 THEN 1 ELSE 0 END) Total_ConfirmedNoViolations,
    SUM(CASE WHEN v.status_id = 4 THEN 1 ELSE 0 END) Total_NotDetermined,
    COUNT(*) Total,
  1  'isAll'
FROM violations v)
ORDER BY country, isAll DESC, site

但是，这种查询的性能可能不是很好，所以我并不是说它是最好的解决方案 - 但它确实有效。

带有“未知”的版本

http://www.sqlfiddle.com/#!2/abfb7/21

(SELECT IF(c.name IS NULL, '- Unknow -', c.name) as name,
    v.site,
    SUM(CASE WHEN v.status_id = 1 THEN 1 ELSE 0 END) Total_SuspectedViolations,
    SUM(CASE WHEN v.status_id = 2 THEN 1 ELSE 0 END) Total_ConfirmedViolations,
    SUM(CASE WHEN v.status_id = 3 THEN 1 ELSE 0 END) Total_ConfirmedNoViolations,
    SUM(CASE WHEN v.status_id = 4 THEN 1 ELSE 0 END) Total_NotDetermined,
    COUNT(*) Total,
    0  'isAll'
FROM violations v LEFT JOIN country c ON c.name = v.country
GROUP BY c.name, v.site)
union(
SELECT IF(c.name IS NULL, '- Unknow -', c.name) as name,
    '- All -',
    SUM(CASE WHEN v.status_id = 1 THEN 1 ELSE 0 END) Total_SuspectedViolations,
    SUM(CASE WHEN v.status_id = 2 THEN 1 ELSE 0 END) Total_ConfirmedViolations,
    SUM(CASE WHEN v.status_id = 3 THEN 1 ELSE 0 END) Total_ConfirmedNoViolations,
    SUM(CASE WHEN v.status_id = 4 THEN 1 ELSE 0 END) Total_NotDetermined,
    COUNT(*) Total,
  1  'isAll'
FROM violations v LEFT JOIN country c ON c.name = v.country
GROUP BY c.name)
UNION (
SELECT '- All -',
    '- All -',
    SUM(CASE WHEN v.status_id = 1 THEN 1 ELSE 0 END) Total_SuspectedViolations,
    SUM(CASE WHEN v.status_id = 2 THEN 1 ELSE 0 END) Total_ConfirmedViolations,
    SUM(CASE WHEN v.status_id = 3 THEN 1 ELSE 0 END) Total_ConfirmedNoViolations,
    SUM(CASE WHEN v.status_id = 4 THEN 1 ELSE 0 END) Total_NotDetermined,
    COUNT(*) Total,
  1  'isAll'
FROM violations v LEFT JOIN country c ON c.name = v.country)
ORDER BY name, isAll DESC, site

Answer 2

使用with rollup，您将获得所需的总和字段

select v.country,
v.site,
SUM(case when s.id = 1 then 1 else 0 end) Total_SuspectedViolations,
SUM(case when s.id = 2 then 1 else 0 end) Total_ConfirmedViolations,
SUM(case when s.id = 3 then 1 else 0 end) Total_ConfirmedNoViolations,
SUM(case when s.id = 4 then 1 else 0 end) Total_NotDetermined,
COUNT(*) Total
from violations v
     inner join status s
     on v.status_id = s.id
group by v.country, v.site WITH ROLLUP

希望对你有帮助

REFER 用于with rollup 文档

FIDDLE