mysql - 可以针对超时异常改进查询吗

如何改进查询，因为它将超时异常。有人能帮我改进查询吗。。。？??

UPDATE pdtdeliveryTable p  SET p.OrderID = IFNULL
(
   (SELECT OrderID from OrderTable o where o.DiagramID=p.DiagramID AND o.DeliveryDate=
   (
        Select min(o2.DeliveryDate) from OrderTable o2 where o2.DiagramId=o.DiagramID Order by o2.DeliveryDate
   )Limit 1),0
)
where p.OrderID=0;

最佳答案

试试这个：

UPDATE pdtdeliveryTable p
LEFT OUTER JOIN (SELECT o.DiagramID, o.OrderID FROM OrderTable o
                 INNER JOIN ( SELECT DiagramID, MIN(DeliveryDate) DeliveryDate
                              FROM OrderTable GROUP BY DiagramID
                            ) AS A ON o.DiagramID = A.DiagramID AND o.DeliveryDate = A.DeliveryDate
               ) AS A ON A.DiagramID = p.DiagramID
SET p.OrderID = IFNULL(A.OrderID, 0);

或者

UPDATE pdtdeliveryTable p
LEFT OUTER JOIN ( SELECT DiagramID, OrderID
                  FROM (SELECT DiagramID, OrderID, DeliveryDate FROM OrderTable ORDER BY DiagramID, DeliveryDate) AS A
                  GROUP BY DiagramID
                ) AS A ON p.DiagramID = A.DiagramID
SET p.OrderID = IFNULL(A.OrderID, 0);

关于mysql - 可以针对超时异常改进查询吗，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/24320612/