我如何加入表上的更新

Question

我有以下查詢：

select  count(L.ID) 
from  LA inner join L on (LA.leadid = L.ID) 
where  L.status = 5 
and   L.city = "cityname" 
and   Date(LA.Datetime) < Date_Sub(Now(), INTERVAL 6 MONTH); 

它會在一個特定的城市是超過6個月（對於存儲在LA的日期與狀態5條記錄）。這返回約4k結果。我想狀態的值更新爲1對每個這樣的記錄，所以我更新的樣子：

update  L, LA 
set   L.status = 1 
where  L.status = 5 
and   L.city = "cityname" 
and   Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH); 

但攤位並鎖定分貝。我懷疑有問題，因爲沒有加入，但我嘗試類似：

update  L, LA 
from  L inner join LA on (L.OID = LA.leadid) 
set   L.status = 1 
where  L.status = 5 
and   L.syscity = "cityname" 
and   Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH); 

，它顯然是行不通的，因爲沒有「從」在更新。

編輯>我使用的是MySQL

Answer 1

update  L 
set   L.status = 1 
where  L.status = 5 
and   L.city = "cityname" 
and   EXISTS (
    select * from LA 
    where Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH) 
    and LA.leadid = L.ID 
) 

Answer 2

我這樣做：

update L 
set status = 1 
from LA 
where L.OID = LA.leadid 
and L.status = 5 
and L.syscity = "cityname" 
and Date(LA.SomeDatetime) < Date_Sub(Now(), INTERVAL 6 MONTH) 

參見：

SQL update from one Table to another based on a ID match

Answer 3

在SQL Server 2005這將工作：

Update L 
    set L.status = 1 
from 
    L 
    -- 
    JOIN LA 
     on (LA.leadid = L.id) 
where 
    L.status = 5 
    and L.city = "cityname" 
    and Date(LA.Datetime) < Date_Sub(Now(), INTERVAL 6 MONTH); 

Answer 4

爲MySQL，你可以使用舊的聯接語法：

UPDATE l, la 
SET  l.status = 1 
WHERE l.status = 5 
    AND l.city = "cityname" 
    AND la.leadid = l.id 
    AND DATE(la.datetime) < DATE_SUB(NOW(), INTERVAL 6 MONTH)