sql - 当结果为空或空白时返回零的 SQL 语句

Question

我正在尝试设置此 SQL 语句，当查询计数为空或空白时将返回零值。

SELECT NAME,
       CASE
         WHEN COUNT(question1) IS NULL THEN 0
         ELSE COUNT(question1)
       END
FROM   INQUIRY2
GROUP  BY name,
          question1
HAVING Question1 = 'Yes'
       AND Name IN ( 'person1', 'person2' ) 

Answer 1

您正在寻找 COALESCE，它返回其参数列表中的第一个非空值。

SELECT NAME, coalesce (COUNT(question1), 0)
FROM INQUIRY2
group by name, question1
having Question1 ='Yes' 
and Name IN ('person1', 'person2')

在这种情况下， COUNT(question1) 似乎不可能为空。