Question

我需要有关mysql查询的帮助。也就是说，我想显示一个结果，即在第一列中包含唯一值，例如，让我们成为四分之一，在第二列中，包含唯一数量的产品。以下查询将引发与数据库的连接。我想征求意见和帮助。

  SELECT DISTINCT(Quarter) AS Column1,
    COUNT(DISTINCT(Product)) as Column2 FROM sample.database
    GROUP BY Column1;

下面的示例表：

id  Quarter     Month           Product
1   Q4 2016  2016-10-01 00:00   Sample 1
2   Q4 2016  2016-10-01 00:00   Sample 1
3   Q4 2016  2016-10-01 00:00   Sample 2
4   Q3 2016  2016-10-01 00:00   Sample 3
5   Q3 2016  2016-10-01 00:00   Sample 3
6   Q3 2016  2016-10-01 00:00   Sample 4
7   Q3 2016  2016-10-01 00:00   Sample 4
8   Q3 2016  2016-10-01 00:00   Sample 4

Answer 1

如果＆＃34;唯一值的总和＆＃34;表示可以使用的唯一值的不同计数：

select Quarter, count(distinct Product)
from data
group by Quarter

Answer 2

第1列您不需要@RequestMapping(method = RequestMethod.GET) public ModelAndView viewMain(Locale locale) { LocaleContextHolder.setLocale(Locale.US); Locale currentLocale = LocaleContextHolder.getLocale(); ModelAndView modelAndView = new ModelAndView(); modelAndView.addObject("locale", currentLocale); LOG.info("main " /* + name*/ + "page shown"); modelAndView.setViewName("main_page"); return modelAndView; }，因为protected $signature = 'db:restore {dataName}'会为您执行此操作，请尝试以下查询：

$this->argument('dataName');

MySql SELECT DISTINCT（x）AS Column1，COUNT（DISTINCT（y））作为Column2 FROM sample.database GROUP BY Column1查询失败

2 个答案: