SELECT從同桌

Question

我試圖做這樣的事情的子集，因此結果是2個獨立的組合選擇

SELECT 
order_number,placed_by,placed_when,updated_by,updated_when, 
(SELECT SUM(qty_order<>qty_rec) 
FROM 1_purchase_orders 
WHERE order_number=order_number AND line_number<>0) 
WHERE 
supp_number=4 AND line_number=0; 

Answer 1

相關子查詢，在查詢中使用時，必須返回只有一個標量值。事情是這樣的：

SELECT 
    t1.order_number, 
    t1.placed_by, 
    t1.placed_when, 
    t1.updated_by, 
    t1.updated_when, 
    (SELECT SUM(t2.qty_order <> t2.qty_rec) 
    FROM 1_purchase_orders t2 
    WHERE t2.order_number = t1.order_number AND t2.line_number <> 0 
    ORDER BY qty_order LIMIT 1) 
FROM 1_purchase_orders t1 
WHERE t1.supp_number = 4 AND t1.line_number=0;