Question

我有一个查询

 select count(api_name),api_name from abc_log where id = '1'
 group by api_name

很好，我得到正确的结果。

假设我的输出是

 count       api_name

   1          abc
   10         123
   12         aaa
   0          xxx

但是我不需要获取计数为'0'的apinames

我该如何编写查询？在此先感谢。

Answer 1

只需添加条件即可过滤出count（api_name）= 0

select count(api_name),api_name from abc_log where id = '1'
 group by api_name 
having count(api_name) <> 0

Answer 2

您可以添加具有子句，如下所示：

select count(api_name),api_name from abc_log where id = '1'
group by api_name 
having count(api_name) > 0

如果您想让名称在0处消失，请尝试以下查询：

select count(api_name) count, 
  CASE count WHEN >0 THEN api_name ELSE ' ' END
from abc_log 
where id = '1'
group by api_name

Answer 3

假设api_name的值为null，则可以将其过滤掉：

select count(api_name), api_name 
from abc_log 
where id = 1 and api_name is not null
group by api_name;

如果id具有数字类型，则无需使用单引号。

Answer 4

您可能还需要考虑以下因素：

with T as (
    select count(api_name) count, api_name
    from abc_log
    where id = '1'
    group by api_name
)
select *
from T
where count > 0

Answer 5

select count(api_name),api_name from abc_log where id = '1'
 group by api_name 
having count(api_name) > 0

尝试一下。乔治的查询也可以正常工作。

Answer 6

此查询：

select count(api_name), api_name 
from abc_log
where id = 1  -- guessing that id is a number
group by api_name ;

当0为api_name时，

只能返回NULL作为计数。对于“ xxx”值，不会发生这种情况。

我的猜测是您的查询更加复杂。

对于此查询，我建议：

select count(api_name), api_name 
from abc_log
where id = 1 and -- guessing that id is a number
      api_name is not null
group by api_name ;

更通用的解决方案是使用having（其他人已经回答了）：

select count(api_name), api_name 
from abc_log
where id = 1 and -- guessing that id is a number
      api_name is not null
group by api_name
having count(api_name) > 0 ;

但是，从性能和清晰度的角度来看，最好在聚合之前进行过滤。

如果count为0，则跳过数据库记录

6 个答案: