Select statement for duplicate record search using 2 different codes

Question

我想在SQL中編寫一個select語句，它將搜索數據庫中有兩個不同代碼的重複記錄。換句話說，它的僞代碼將是

選擇發票編號，其中m_code = J或T.這會給我的發票號碼2345兩次，一次用代碼J和曾經與代碼T.

Answer 1

如果你正在尋找對於特定的代碼，那麼你可以使用WHERE子句過濾用HAVING和GROUP BY：

select invoice 
from yourtable 
where m_code in ('J', 'T') 
group by invoice 
having count(distinct m_code) > 1; 

但是，如果你想返回，並與任何兩張發票重複m_codes那麼你可以使用：

select invoice 
from yourtable 
group by invoice 
having count(distinct m_code) > 1; 

同時看到的SQL Fiddle with Demo查詢

Answer 2

Select invoice_numbers,COUNT(DISTINCT m_code) as CNT 
FROM TABLE where m_code in('J','T') 
GROUP BY invoice_numbers 
HAVING CNT >1; 

FIDDLE