Question

我需要根据不同的标准在同一个查询中得到两个求和。两个标准都在同一列上运行。有没有办法做到这一点？

我最好用一个例子解释一下：

表：   salary_survey_result

柱：   行业，   地点，   位置，   薪水

实际上我想要结合以下两个查询：

SELECT industry, location, count(*) as MORE_THAN_SIX_FIGURE   
FROM salary_survey_result  
WHERE salary > 100000  
GROUP BY industry, location

和

SELECT industry, location, count(*) as MORE_THAN_FIVE_FIGURE  
FROM salary_survey_result  
WHERE salary > 10000  
GROUP BY industry, location

所以结果是这样的：
industry location MORE_THAN_FIVE_FIGURE MORE_THAN_SIX_FIGURE

Healthcare    NY               45                      10  
Healthcare    MN               35                       6   
InfoTech      NY               50                      19
InfoTech      MN               40                      12

Answer 1

像

这样的东西

SELECT industry, 
       location, 
       sum( case when salary >= 10000 then 1 else 0 end) as MORE_THAN_FIVE_FIGURE,
       sum( case when salary >= 100000 then 1 else 0 end) as MORE_THAN_SIX_FIGURE
  FROM salary_survey_result  
  WHERE salary >= 10000  
  GROUP BY industry, location

结果不需要WHERE salary >= 10000子句。如果SALARY上有索引并且大多数工资值小于10000，它可能会提高性能。请注意，我还假设你的意思是>=而不是>，因为工资是10,000是五位数的薪水。

Answer 2

SELECT industry, location, count(*) as MORE_THAN_FIVE_FIGURE ,sum(salary > 100000) as MORE_THAN_SIX_FIGURE
FROM salary_survey_result  
WHERE salary > 10000  
GROUP BY industry, location

两个WHERE＆amp;一个查询中有COUNT个

2 个答案: