Question

这样的表格

我尝试下一个SELECT：

    SELECT  accounts.name, accounts.account_id,date,  
  (case  when accounts.account_id = results.account_id then date  end) AS Dat,  
results.account_id 
FROM results 
INNER JOIN accounts 
group by date,dat,name 
order by accounts.account_id ,date

但我有不必要的领域。帮助摆脱它们。

此外： 我必须这样表格：

--------------------01.2010----02.2010-----03.2010---nextDate

Revenues ----------'x'------------'x'---------'null'---------------------

Personal Costs-----'x'------------'x'---------'x'---------------------

Amortisation---------'x'------------'x'---------'null'---------------------

Summa---------------'3x'-----------'3x'---------'1x'---------------------

我使用下一个选择：

SELECT 
GROUP_CONCAT(revenues SEPARATOR ';')as Renenues, 
GROUP_CONCAT(personal  SEPARATOR ';')as Personal, 
GROUP_CONCAT(amortisation  SEPARATOR ';')as Amortisation
from (SELECT  date, 
sum(case  when accounts.account_id = 1 then 1 else 0 end) as revenues,
sum(case  when accounts.account_id = 2 then 1 else 0 end) as personal ,
sum(case  when  accounts.account_id = 3 then 1 else 0  end) as amortisation
from accounts
left JOIN results on accounts.account_id = results.account_id
group by date
) t
UNION ALL
SELECT
sum(case  when results.account_id = 1 then 1 ELSE 0  end) ,
sum(case  when results.account_id = 2 then 1 else 0 end) ,
sum(case  when  results.account_id = 3 then 1 else 0  end) 
 from results

然后我将从我的字符串中显示表格行：'GROUP_CONCAT'。可以使SELECT不知道'accounts.account_id'的数量或优化这个SELECT？我尝试了第一个SELECT但得到了很多不必要的信息。

Answer 1

您应该将查询修改为

SELECT  accounts.name, 
accounts.account_id as accounts_account_id,
accounts.date,  
results.account_id  as results_account_id
FROM results 
LEFT JOIN accounts ON accounts.account_id = results.account_id
group by accounts.date,accounts.name 
order by accounts.account_id ,accounts.date;

如何优化内连接

1 个答案: