Mysql JOIN：只有在多個連接匹配的行匹配時纔會選擇

Question

我在想這裏的某個人是否可以幫我重述這個，所以我只從works得到結果if works。 id + prod_instruments_id + number全部都在works_instruments？

這是我有：

SELECT 
    `works`.`id`, 
    `composers`.`first_name` 
FROM `works` 
    JOIN `composers` ON `works`.`composers_id` = `composers`.`id` 
    JOIN `works_instruments` ON `works`.`id` = `works_instruments`.`works_id` 
WHERE 
    (true) 
    AND `composers`.`full_name` LIKE '%karl friedrich abel%' 
    AND `works_instruments`.`prod_dd_instruments_id` = 15 
    AND `works_instruments`.`number` >= 1 
    AND `works_instruments`.`prod_dd_instruments_id` = 5 
    AND `works_instruments`.`number` >= 1 
    AND `works`.`work_no` <> '001' AND `works`.`short_title` NOT LIKE '%*Works' 
ORDER BY 
    `composers`.`last_name`, 
    `composers`.`first_name`, 
    `works`.`full_title` 
LIMIT 0,50 

眼下這種不返回任何結果。 但是這並不：

SELECT 
    `works`.`id`, 
    `composers`.`first_name` 
FROM `works` 
    JOIN `composers` ON `works`.`composers_id` = `composers`.`id` 
    JOIN `works_instruments` ON `works`.`id` = `works_instruments`.`works_id` 
WHERE 
    (true) 
    AND `composers`.`full_name` LIKE '%karl friedrich abel%' 
    AND `works_instruments`.`prod_dd_instruments_id` = 15 
    AND `works_instruments`.`number` >= 1 
    AND `works`.`work_no` <> '001' AND `works`.`short_title` NOT LIKE '%*Works' 
ORDER BY 
    `composers`.`last_name`, 
    `composers`.`first_name`, 
    `works`.`full_title` 
LIMIT 0,50 

而且這樣做：

SELECT 
    `works`.`id`, 
    `composers`.`first_name` 
FROM `works` 
    JOIN `composers` ON `works`.`composers_id` = `composers`.`id` 
    JOIN `works_instruments` ON `works`.`id` = `works_instruments`.`works_id` 
WHERE 
    (true) 
    AND `composers`.`full_name` LIKE '%karl friedrich abel%' 
    AND `works_instruments`.`prod_dd_instruments_id` = 5 
    AND `works_instruments`.`number` >= 1 
    AND `works`.`work_no` <> '001' AND `works`.`short_title` NOT LIKE '%*Works' 
ORDER BY 
    `composers`.`last_name`, 
    `composers`.`first_name`, 
    `works`.`full_title` 
LIMIT 0,50 

你能幫忙嗎？

我也嘗試過左，右加盟，但仍然是一個空的結果（我只在這裏貼左）：

SELECT 
    `works`.`id`, 
    `composers`.`first_name` 
FROM `works` 
    JOIN `composers` ON `works`.`composers_id` = `composers`.`id` 
    LEFT JOIN `works_instruments` ON `works`.`id` = `works_instruments`.`works_id` 
WHERE 
    (true) 
    AND `composers`.`full_name` LIKE '%karl friedrich abel%' 
    AND `works_instruments`.`prod_dd_instruments_id` = 15 
    AND `works_instruments`.`number` >= 1 
    AND `works_instruments`.`prod_dd_instruments_id` = 5 
    AND `works_instruments`.`number` >= 1 
    AND `works`.`work_no` <> '001' AND `works`.`short_title` NOT LIKE '%*Works' 
ORDER BY 
    `composers`.`last_name`, 
    `composers`.`first_name`, 
    `works`.`full_title` 
LIMIT 0,50 

難道works_instruments沒有潮頭ID的問題？ 見的works_instruments這裏截圖： Screenshot

Answer 1

沒有數值，其中一個字段可以= 15，= 5在同一時間。相反，你可以通過works.id做「IN（15，5）」，然後計算不同的prod_dd_instruments_id值來查看是否有兩個;或者使用不同的標準集合對同一個表進行兩個單獨的連接。

編輯：有了你在下面給出的附加信息，類似這樣的東西可能會更有幫助。

SELECT works.*, composers.* 
, SUM(IF(wi.prod_dd_instruments_id=15, wi.number, 0)) AS count15 
, SUM(IF(wi.prod_dd_instruments_id=5, wi.number, 0)) AS count5 
FROM works 
INNER JOIN `composers` ON `works`.`composers_id` = `composers`.`id` 
LEFT JOIN `works_instruments` AS wi ON `works`.`id` = wi.`works_id` 
WHERE [the other criteria you had] 
GROUP BY works.id 
HAVING count15 > 1 AND count5 > 1 
; 

注意這個查詢只適用於 「5 & 15」;雖然（從你的「(true)」我hazarding你部分的代碼構建查詢在租賃猜測來判斷，所以我認爲這將不會太困難，使上述多一點的代碼靈活。