mysql - 限制计数，其余为 "Others"

Question

我正在计算要在饼图中显示的内容。我想仅显示实际投资类型的最高 6 个计数，其余的作为投资类型显示为“其他”。

SELECT i.investment_type AS investmentType,
       COUNT(*) AS investmentCount 
  FROM investment i,
       vertical v 
 WHERE v.vertical_name = i.investment_type 
   AND v.type = 'STR' 
   AND i.status_funding = 'o' 
 GROUP 
    BY i.investment_type 
 ORDER 
    BY investmentCount desc

上面的查询给了我一个结果

通过将 limit 6 添加到我得到的查询中

我需要的是另一行投资类型“其他”和投资计数“7”。

Answer 1

您可能想尝试以下操作:

    SELECT i.investment_type as investmentType,COUNT(*) as investmentCount FROM investment i,vertical v 
    WHERE v.vertical_name  =i.investment_type AND v.type='STR' AND i.status_funding ='o' 
    group by i.investment_type order by investmentCount desc
    limit 6
UNION
    SELECT "others" as investmentType, SUM(othersInvestmentCount) as investmentCount FROM (
        SELECT COUNT(*) as othersInvestmentCount FROM investment i,vertical v 
        WHERE v.vertical_name  =i.investment_type AND v.type='STR' AND i.status_funding ='o' 
        group by i.investment_type order by investmentCount desc
        limit 6, 4294967296
    )

我没有测试这个查询，如果您发现语法问题，可以编辑它。涉及三个实际查询，但它不应该太慢(如果不需要更快，则无需尝试更快)。

我假设您的数据库中的记录少于 2^32 条，这对于 MySQL 数据库来说似乎是一个非常合理的假设(但如果您觉得不安全，只需将其替换为 2^64)。