結合3個MySQL查詢進行1次查詢

Question

我正在嘗試在我的網站中構建搜索功能。 如果我想搜索照片的標題，文字或標簽是否包含“黑色”這個詞，我有以下3個查詢：

SELECT id 
FROM photos 
WHERE title LIKE '%black%' 
AND status = 'A'

SELECT id 
FROM photos 
WHERE text LIKE '%black%' 
AND status = 'A'

SELECT DISTINCT(photos.id) 
FROM photos, photo_tags, tags 
WHERE tags.tag LIKE '%black%' 
AND photo_tags.keyid = tags.id 
AND photos.id = photo_tags.catid 
AND photos.status = 'A'

是否可以將所有這些組合成1個查詢？ 我知道我可以加入第一個2但是將它與第三個相結合對我來說似乎太復雜了。 我嘗試加入OR，但我不認為我做得對。

此外，我希望它沒有重復的結果，所以如果一張照片的標題為“黑色”，標簽為“黑色”，它只會出現一次。

BTW表格看起來像這樣，keyid與tag.id有關，catid與photos.id有關

photos

+----+-----------+-----------------+
| id | title     | text            |
+----+-----------------------------+
|  1 | blue pic  | black and blue  |
|  2 | red pic   | red and green   |
|  3 | green pic | green and white |
|  4 | white pic | white and black |
|  5 | black pic | black and gold  |
+----+-----------+-----------------+

tags

+----+-------+
| id | tag   |
+----+-------+
|  1 | blue  |
|  2 | table |
|  3 | chair |
|  4 | red   |
|  5 | black |
+----+-------+

photo_tags

+-------+-------+
| keyid | catid |
+-------+-------+
|  1    | 1     |
|  2    | 1     |
|  3    | 2     |
|  4    | 2     |
|  5    | 5     |
+-------+-------+    

Answer 1

您似乎應該加入表格，然后根據您在兩個表格中查找的文本進行過濾：

SELECT DISTINCT p.id FROM photos p
JOIN photo_tags pt ON pt.cat_id = p.id
JOIN tags t ON pt.key_id = t.id
WHERE (p.title LIKE '%black%' OR t.tag LIKE '%black%') AND p.status = 'A'

Answer 2

First statement could be your answer. Not sure if you are looking for below output:-

ysql> SELECT DISTINCT(photos.id) FROM photos, photo_tags, tags WHERE tags.tag L
IKE '%black%'AND photos.title LIKE '%black%' AND photo_tags.keyid = tags.id AND
photos.id = photo_tags.catid;
+------+
| id   |
+------+
|    5 |
+------+
1 row in set (0.05 sec)


mysql> SELECT id
    -> FROM photos
    -> WHERE title LIKE '%black%' ;
+------+
| id   |
+------+
|    5 |
+------+
1 row in set (0.08 sec)

mysql> SELECT id
    -> FROM photos
    -> WHERE text LIKE '%black%';
+------+
| id   |
+------+
|    1 |
|    4 |
|    5 |
+------+
3 rows in set (0.00 sec)

mysql> SELECT DISTINCT(photos.id)
    -> FROM photos, photo_tags, tags
    -> WHERE tags.tag LIKE '%black%'
    -> AND photo_tags.keyid = tags.id
    -> AND photos.id = photo_tags.catid ;
+------+
| id   |
+------+
|    5 |
+------+
1 row in set (0.05 sec)



mysql> SELECT DISTINCT(photos.id) FROM photos, photo_tags, tags WHERE tags.tag L
IKE '%black%'AND photos.title LIKE '%black%' AND photo_tags.keyid = tags.id AND
photos.id = photo_tags.catid;
+------+
| id   |
+------+
|    5 |
+------+
1 row in set (0.05 sec)