如何使用WHERE子句在MySql中更新字段形成select語句？

Question

我想從select語句更新一個字段。這是我目前的查詢

UPDATE phone_cals 
SET call_code_id = id, result_code_id = 0, call_subject = title WHERE status = 1 
select call_code_id AS id, call_code_title AS title FROM call_codes 

我想設置

phone_calls.call_code_id = call_codes.call_code_id 
phone_calls.result_code_id = 0 
phone_calls.call_subject = call_codes.call_code_title 

WHERE phone_calls.status = 1 

是的，我有一個語法錯誤，但我不知道如何解決它

綜述我想選擇一個隨機call_codes.call_code_id並將其分配給phone_calls.call_code_id

Answer 1

如果我正確理解你的問題，我認爲你需要這樣的事情：

UPDATE 
    phone_calls, 
    (select call_code_id, call_code_title FROM call_codes ORDER BY rand() LIMIT 1) c2 
SET 
    phone_calls.call_code_id = c2.call_code_id, 
    phone_calls.result_code_id = 0, 
    phone_calls.call_subject = c2.call_code_title 
WHERE 
    phone_calls.call_subject = 1 

這將更新所有call_code_id和所有call_subject從call_codes表，其中call_subject = 1選擇了一個隨機值。

編輯

如果您需要在每一行更新爲不同的隨機值，我想你可以這樣做：

UPDATE 
    phone_calls 
SET 
    call_code_id = (select call_code_id FROM call_codes ORDER BY rand() LIMIT 1), 
    result_code_id = 0 
WHERE 
    phone_calls.call_subject = 1; 

UPDATE 
    phone_calls INNER JOIN call_codes 
    ON phone_calls.call_code_id = call_codes.call_code_id 
SET 
    phone_calls.call_subject = call_codes.call_code_title 
WHERE 
    phone_calls.call_subject = 1; 

（不知道是否有可能用做只是一個查詢）。它可能很慢，但它應該工作。