## MySQL'de JOIN ve UNION Kullan\u0131m\u0131<\/p>
MySQL'de `JOIN` ve `UNION` ifadeleri, birden fazla tablodan veri \u00e7ekmek ve bu verileri birle\u015ftirmek i\u00e7in kullan\u0131l\u0131r. Bu b\u00f6l\u00fcmde, bu ifadelerin farkl\u0131 kullan\u0131m senaryolar\u0131n\u0131 ve ipu\u00e7lar\u0131n\u0131 inceleyece\u011fiz.<\/p>
### 1. **JOIN ile Tablolar\u0131 Birle\u015ftirme**<\/p>
`JOIN` ifadesi, iki veya daha fazla tablodan veri \u00e7ekmek ve bu verileri belirli bir ko\u015fula g\u00f6re birle\u015ftirmek i\u00e7in kullan\u0131l\u0131r. MySQL'de farkl\u0131 `JOIN` t\u00fcrleri bulunur:<\/p>
- **INNER JOIN:** \u0130ki tablodaki e\u015fle\u015fen kay\u0131tlar\u0131 d\u00f6ner.
- **LEFT JOIN:** Sol tablodaki t\u00fcm kay\u0131tlar\u0131 ve sa\u011f tablodaki e\u015fle\u015fen kay\u0131tlar\u0131 d\u00f6ner. E\u015fle\u015fmeyen kay\u0131tlar i\u00e7in `NULL` de\u011fer d\u00f6ner.
- **RIGHT JOIN:** Sa\u011f tablodaki t\u00fcm kay\u0131tlar\u0131 ve sol tablodaki e\u015fle\u015fen kay\u0131tlar\u0131 d\u00f6ner. E\u015fle\u015fmeyen kay\u0131tlar i\u00e7in `NULL` de\u011fer d\u00f6ner.
- **FULL OUTER JOIN:** MySQL'de do\u011frudan desteklenmez, ancak `UNION` ile taklit edilebilir.<\/p>
**\u00d6rnek Kullan\u0131m (INNER JOIN):**
```sql
SELECT user.name, course.name
FROM user
INNER JOIN course ON user.course = course.id;
```<\/p>
Bu sorgu, `user` tablosundaki her kullan\u0131c\u0131n\u0131n ad\u0131n\u0131 ve `course` tablosundaki ilgili kursun ad\u0131n\u0131 d\u00f6ner.<\/p>
**\u00d6rnek Kullan\u0131m (LEFT JOIN):**
```sql
SELECT user.name, course.name
FROM user
LEFT JOIN course ON user.course = course.id;
```<\/p>
Bu sorgu, `user` tablosundaki t\u00fcm kullan\u0131c\u0131lar\u0131 ve e\u015fle\u015fen kurslar\u0131 d\u00f6ner. E\u011fer bir kullan\u0131c\u0131n\u0131n kursu yoksa, kurs ad\u0131 `NULL` olarak d\u00f6ner.<\/p>
### 2. **FULL OUTER JOIN Taklidi**<\/p>
MySQL'de `FULL OUTER JOIN` do\u011frudan desteklenmez, ancak `LEFT JOIN` ve `RIGHT JOIN` kullan\u0131larak taklit edilebilir.<\/p>
**\u00d6rnek Kullan\u0131m:**
```sql
SELECT owners.owner, tools.tool
FROM owners
LEFT JOIN tools ON owners.owner_id = tools.owner_id
UNION ALL
SELECT owners.owner, tools.tool
FROM owners
RIGHT JOIN tools ON owners.owner_id = tools.owner_id
WHERE owners.owner_id IS NULL;
```<\/p>
Bu sorgu, `owners` ve `tools` tablolar\u0131ndaki t\u00fcm kay\u0131tlar\u0131 birle\u015ftirir. E\u015fle\u015fmeyen kay\u0131tlar i\u00e7in `NULL` de\u011ferler d\u00f6ner.<\/p>
### 3. **UNION ile Sorgular\u0131 Birle\u015ftirme**<\/p>
`UNION` ifadesi, iki veya daha fazla `SELECT` sorgusunun sonu\u00e7lar\u0131n\u0131 birle\u015ftirmek i\u00e7in kullan\u0131l\u0131r. Varsay\u0131lan olarak, `UNION` yinelenen kay\u0131tlar\u0131 kald\u0131r\u0131r. E\u011fer yinelenen kay\u0131tlar\u0131 korumak istiyorsan\u0131z, `UNION ALL` kullanabilirsiniz.<\/p>
**\u00d6rnek Kullan\u0131m:**
```sql
SELECT name, email, phone_number
FROM authors
UNION
SELECT name, email, phone_number
FROM editors;
```<\/p>
Bu sorgu, `authors` ve `editors` tablolar\u0131ndaki t\u00fcm ad, e-posta ve telefon numaras\u0131 bilgilerini birle\u015ftirir ve yinelenen kay\u0131tlar\u0131 kald\u0131r\u0131r.<\/p>
**\u00d6rnek Kullan\u0131m (UNION ALL):**
```sql
SELECT name, email, phone_number
FROM authors
UNION ALL
SELECT name, email, phone_number
FROM editors;
```<\/p>
Bu sorgu, `authors` ve `editors` tablolar\u0131ndaki t\u00fcm ad, e-posta ve telefon numaras\u0131 bilgilerini birle\u015ftirir ve yinelenen kay\u0131tlar\u0131 korur.<\/p>
### 4. **ORDER BY ve LIMIT ile UNION Kullan\u0131m\u0131**<\/p>
`UNION` ile birle\u015ftirilen sorgular\u0131n sonu\u00e7lar\u0131n\u0131 s\u0131ralamak ve s\u0131n\u0131rlamak i\u00e7in `ORDER BY` ve `LIMIT` kullan\u0131labilir.<\/p>
**\u00d6rnek Kullan\u0131m:**
```sql
(SELECT name, email FROM authors ORDER BY name LIMIT 10)
UNION
(SELECT name, email FROM editors ORDER BY name LIMIT 10)
ORDER BY name LIMIT 10;
```<\/p>
Bu sorgu, `authors` ve `editors` tablolar\u0131ndaki ilk 10 kayd\u0131 birle\u015ftirir ve sonu\u00e7lar\u0131 `name` s\u00fctununa g\u00f6re s\u0131ralar.<\/p>
### 5. **JOIN ile Alt Sorgu Kullan\u0131m\u0131**<\/p>
`JOIN` ifadesi, alt sorgular (subqueries) ile birlikte kullan\u0131labilir. Bu, \u00f6zellikle karma\u015f\u0131k sorgularda kullan\u0131\u015fl\u0131d\u0131r.<\/p>
**\u00d6rnek Kullan\u0131m:**
```sql
SELECT user.name, course.name
FROM user
INNER JOIN (SELECT id, name FROM course WHERE id > 5) AS course ON user.course = course.id;
```<\/p>
Bu sorgu, `course` tablosundaki `id` de\u011feri 5'ten b\u00fcy\u00fck olan kurslar\u0131 `user` tablosu ile birle\u015ftirir.<\/p>
---<\/p>
Bu bilgilerle, MySQL'de `JOIN` ve `UNION` ifadelerinin farkl\u0131 kullan\u0131m senaryolar\u0131n\u0131 ve ipu\u00e7lar\u0131n\u0131 daha iyi anlayabilirsiniz. Bir sonraki yaz\u0131da, alt sorgular ve daha geli\u015fmi\u015f SQL konular\u0131na de\u011finece\u011fiz.<\/p>
<\/p>","excerpt":"MySQL'de `JOIN` ve `UNION` ifadelerinin farkl\u0131 kullan\u0131m senaryolar\u0131n\u0131 ve ipu\u00e7lar\u0131n\u0131 daha iyi anlayabilirsiniz. Bir sonraki yaz\u0131da, alt sorgular ve daha geli\u015fmi\u015f SQL konular\u0131na de\u011finece\u011fiz.","created_at":"2025-01-13 15:02:58","updated_at":"2026-09-23 20:07:43","category_id":9,"view_count":551,"reading_time":4,"status":"published","editor_choice":0,"is_editor_choice":0,"published_at":"2025-01-13 15:02:58","featured_image":"resimyok.jpg","slug":"sql-notlari-join-ve-union-kullanimi","category_name":"Yaz\u0131l\u0131m","category_slug":"yazilim"}