顯示ROWNUM問題的MySQL

Question

我有這個疑問：

SET @row_num = 0; 
SELECT 
(SELECT @row_num := @row_num + 1) AS itempurchase_code, 
(SELECT supplier_code FROM qa_items_purchases a WHERE a.item_invoicecodesupplier = b.item_invoicecodesupplier GROUP BY supplier_code ORDER BY COUNT(*) DESC LIMIT 1) AS supplier_code, 
(SELECT user_code FROM qa_items_purchases a WHERE a.item_invoicecodesupplier = b.item_invoicecodesupplier GROUP BY user_code ORDER BY COUNT(*) DESC LIMIT 1) AS user_code, 
22 AS status_code, 
item_invoicecodesupplier AS item_invoicecodesupplier, 
(SELECT itempurchase_date FROM qa_items_purchases a WHERE a.item_invoicecodesupplier = b.item_invoicecodesupplier GROUP BY itempurchase_date ORDER BY COUNT(*) DESC LIMIT 1) AS itempurchase_date 
FROM qa_items_purchases b 
GROUP BY (item_invoicecodesupplier) 
ORDER BY itempurchase_code; 

我得到這樣的結果：

如果你看看有沒有（2）itempurchase_code列，我能做些什麼來顯示數字按順序？

Answer 1

如果查詢包含GROUP BY，則必須在外部查詢中添加行號。

SET @row_num = 0; 
SELECT (SELECT @row_num := @row_num + 1) AS itempurchase_code, * 
FROM 
(
    SELECT ... -- your original query goes here 
) AS T1 
ORDER BY itempurchase_code