如何使用条件计数器获取数据 Mysql 组答案

【问题标题】：How to get data Mysql group by with condition counter如何使用条件计数器获取数据 Mysql 组
【发布时间】：2019-09-10 22:28:00
【问题描述】：

Mysql 按计数器分组（多少个条件）

大家好

我想；

question_id 1 和答案 2
question_id 2 和 answer 2
question_id 3 和 ve 回答 2
question_id 4 和 ve 回答 2
question_id 5 和 ve 回答 2

我想按 object_id 分组，看看哪个 object_id 与一个名为 match_number 的字段中有多少条件匹配。

喜欢结果；

Object_id   Eşleşme_sayısı
    1             3
    2             5

筛选表格；

表sql代码；

CREATE TABLE `object_answers` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `question_id` int(11) unsigned DEFAULT NULL,
  `object_id` int(11) unsigned DEFAULT NULL,
  `answer` int(2) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `object_answers_question_id_foreign` (`question_id`),
  KEY `object_answers_object_id_foreign` (`object_id`),
  CONSTRAINT `object_answers_object_id_foreign` FOREIGN KEY (`object_id`) REFERENCES `object` (`id`) ON DELETE CASCADE,
  CONSTRAINT `object_answers_question_id_foreign` FOREIGN KEY (`question_id`) REFERENCES `question` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=51 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `object_answers` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `question_id` int(11) unsigned DEFAULT NULL,
  `object_id` int(11) unsigned DEFAULT NULL,
  `answer` int(2) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `object_answers_question_id_foreign` (`question_id`),
  KEY `object_answers_object_id_foreign` (`object_id`),
  CONSTRAINT `object_answers_object_id_foreign` FOREIGN KEY (`object_id`) REFERENCES `object` (`id`) ON DELETE CASCADE,
  CONSTRAINT `object_answers_question_id_foreign` FOREIGN KEY (`question_id`) REFERENCES `question` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=51 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

【问题讨论】：

图片 => i.hizliresim.com/dvmDR7.png
请澄清您的具体问题或添加其他详细信息以准确突出您的需要。正如目前所写的那样，很难准确地说出你在问什么。请参阅如何提问页面以帮助澄清此问题
要发布表的内容（这在 SQL 问题中是一件好事）使用 INSERT INTO 语句但 no 图像。

标签： mysql conditional-statements counter

【解决方案1】：

您可以使用 MySQL 在数字上下文中将布尔表达式转换为 0 或 1 的能力。因此，您可以间接对布尔表达式求和。

SELECT obejct_id,
       sum(question_id IN (1, 2, 3, 4, 5)
           AND answer = 2) "Eşleşme_sayısı"
       FROM object_answers
       GROUP BY object_id;

【讨论】：