GROUP BY 同一列中的多个值

2021-09-10 00:00:00 sql tsql sql-server

我有这个 SQL 查询:

I have this SQL Query:

select prefix, code, stat, complete, COUNT(*) as Count
from table
group by prefix, code, stat, complete
order by prefix, code, stat, complete

前缀"列是一个字母数字值 (0-9a-zA-z).我想要的是让它如果前缀的值是一个数字，使数字等于0.如果它是一个字母，它会保持它的值.我试图在 group by 子句下面添加以下行:

The column 'prefix' is an alphanumeric value (0-9a-zA-z). What I want is to make it so that if the value of prefix is a number, to make the number equal to 0. If it is a letter, it will keep its value. I have tried to add the following line beneath the group by clause:

(case when prefix like '%[0-9]%' then 0 else prefix end)

但我收到错误消息将 varchar 值 'J' 转换为数据类型 int 时转换失败.".

But I get an error "Conversion failed when converting the varchar value 'J' to data type int.".

是什么导致了这个错误?如何让前缀"列显示 0 或一个字母?

What is causing this error? How can I get the 'prefix' column to display either 0 or a letter?

推荐答案

case when prefix like '%[0-9]%' then '0' else prefix end

你显然也需要这个作为 GROUP BY 中的表达式:

You obviously also need this as the expression in the GROUP BY:

select 
    NewPrefix = case when prefix like '%[0-9]%' then '0' else prefix end, 
    code, 
    stat, 
    complete, 
    COUNT(*) as Count
from table
group by 
    case when prefix like '%[0-9]%' then '0' else prefix end, 
    code, stat, complete
order by 
    case when prefix like '%[0-9]%' then '0' else prefix end, 
    code, stat, complete

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