Question

我需要计算一列中的不同值。它是Char数据类型。我在oracle中编写了我的代码，但是我无法更改SQL Server中的语法;

这有效：

Select l.name, l.address,
       SUM(DECODE(L.SEX,   'M',   1,   0)) MALE_TOTAL,
       SUM(DECODE(L.SEX,   'F',   1,   0)) FEMALE_TOTAL,
       SUM(DECODE(L.SEX,   'U',   1,   0)) UNKNOWN_TOTAL
From personnel

非常感谢

Answer 1

您想要的SQL标准方法是：

Select l.name, l.address,
       SUM(CASE WHEN L.SEX = 'M' THEN 1 ELSE 0 END) MALE_TOTAL,
       SUM(CASE WHEN L.SEX = 'F' THEN 1 ELSE 0 END) FEMALE_TOTAL,
       SUM(CASE WHEN L.SEX = 'U' THEN 1 ELSE 0 END) UNKNOWN_TOTAL
From personnel
group by l.name, l.address;

请注意GROUP BY。如果你想要每个名称/地址一行，那么你需要这个。否则，请从SELECT：

中删除列

Select SUM(CASE WHEN L.SEX = 'M' THEN 1 ELSE 0 END) MALE_TOTAL,
       SUM(CASE WHEN L.SEX = 'F' THEN 1 ELSE 0 END) FEMALE_TOTAL,
       SUM(CASE WHEN L.SEX = 'U' THEN 1 ELSE 0 END) UNKNOWN_TOTAL
From personnel;

Answer 2

您可以使用IIF 2012 +

https://docs.microsoft.com/en-us/sql/t-sql/functions/logical-functions-iif-transact-sql

SELECT
  SUM(IIF(L.SEX = 'M', 1, 0)) MALE_TOTAL,
  SUM(IIF(L.SEX = 'F', 1, 0)) FEMALE_TOTAL,
  SUM(IIF(L.SEX = 'U', 1, 0)) UNKNOWN_TOTAL
FROM personnel

OR CASE

SELECT
  SUM(case when L.SEX = 'M' then 1 else 0 end)) MALE_TOTAL,
  SUM(case when L.SEX = 'F' then 1 else 0 end) FEMALE_TOTAL,
  SUM(case when L.SEX = 'U' then 1 else 0 end) UNKNOWN_TOTAL
FROM personnel

一列中Char值的总和

2 个答案: