Dalabka midowga iyadoo la adeegsanayo syntax/hadalka adeegsiga xogta MySQL

database MySQLDalabka ururka iyadoo la adeegsanayo syntax/hadal weydiin

MySQL Hawlwadeenka UNION

Casharadani waxa ay ku baraysaa hab-raacyada iyo tusaalooyinka hawlwadeenka MySQL UNION.

sharaxaad

Hawl wadeenka MySQL UNION waxa loo isticmaalaa in lagu daro natiijooyinka laba ama in ka badan oo ah SELECT weedho oo laga dhigo hal natiijo.Odhaahyo badan oo SELECT ayaa meesha ka saaraya xogta nuqul ka mid ah

naxwaha

MySQL UNION qaabka syntax hawlwadeenka:

SELECT expression1, expression2, ... expression_n
FROM tables
[WHERE conditions]
UNION [ALL | DISTINCT]
SELECT expression1, expression2, ... expression_n
FROM tables
[WHERE conditions];

Xusuus

• tibaax1, tibaax2, ... tibaax_n: Sadar si loo soo saaro.
• miisaska: Jadwalka xogta si loo soo saaro.
• Halkee shuruudaha: Ikhtiyaar ah, shuruudaha raadinta.
• KALA DUWAN: Ikhtiyaar ahaan, ka saar xogta nuqul ka mid ah natiijada.Hawl wadeenka UNION wuxuu si caadi ah u kala saaray xogta, markaa wax ka beddelka DISTINCT wax saamayn ah kuma laha natiijada.
• DHAMMAAN: Ikhtiyaar ah, soo celisa dhammaan natiijada natiijooyinka, oo ay ku jiraan nuqullo.

database demo

Tababarkan, waxaan ku isticmaali doonaa xogta muunada chenweiliang.

Waa kan xogta laga helay miiska "Websites":

mysql> SELECT * FROM Websites;
+----+--------------+---------------------------+-------+---------+
| id | name         | url                       | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1  | Google       | https://www.google.cm/    | 1     | USA     |
| 2  | 淘宝          | https://www.taobao.com/   | 13    | CN      |
| 3  | 陈沩亮博客      | http://www.chenweiliang.com/    | 4689  | CN      |
| 4  | 微博          | http://weibo.com/         | 20    | CN      |
| 5  | Facebook     | https://www.facebook.com/ | 3     | USA     |
| 7  | stackoverflow | http://stackoverflow.com/ |   0 | IND     |
+----+---------------+---------------------------+-------+---------+

Waa kan xogta "apps" APP:

mysql> SELECT * FROM apps;
+----+------------+-------------------------+---------+
| id | app_name   | url                     | country |
+----+------------+-------------------------+---------+
|  1 | QQ APP     | http://im.qq.com/       | CN      |
|  2 | 微博 APP | http://weibo.com/       | CN      |
|  3 | 淘宝 APP | https://www.taobao.com/ | CN      |
+----+------------+-------------------------+---------+
3 rows in set (0.00 sec)

Tusaale ahaan SQL UNION

Bayaankan soo socda ee SQL ayaa ka wada dooranaya "Websites" iyo "apps" miisaskakala duwandalka (kaliya qiyam kala duwan):

SELECT country FROM Websites
UNION
SELECT country FROM apps
ORDER BY country;

SQL UNION ALL tusaale ahaan

Odhaahda SQL ee soo socota waxay isticmaashaa UNION ALL si ay uga xusho miisaska "Websites" iyo "apps".dhanwadanka (sidoo kale waxa uu leeyahay qiyamyo nuqul ah):

SELECT country FROM Websites
UNION ALL
SELECT country FROM apps
ORDER BY country;

SQL UNION DHAMMAAN oo leh HALKEE

Odhaahda SQL ee soo socota waxay isticmaashaa UNION ALL si ay uga xusho miisaska "Websites" iyo "apps".dhanXogta Shiinaha (CN) (sidoo kale leh qiimayaal nuqul ah):

SELECT country, name FROM Websites
WHERE country='CN'
UNION ALL
SELECT country, app_name FROM apps
WHERE country='CN'
ORDER BY country;