Ismail Hussaini Alpholtawy

TYPES OF JOIN IN SQL:

Bayanin LEFT JOIN da Hausa

Kamar yadda na fada a post nawa na farko akan JOINs cewa, akwai kashe-kashen JOINs guda 4 a SQL da zanyi magana akai, kamar haka:

  • INNER JOIN
  • LEFT JOIN
  • RIGHT JOIN
  • FULL JOIN

Nayi bayanin INNER JOIN, yau insha Allah zanyi bayani akan LEFT JOIN.

  1. LEFT JOIN

Duk lokacin da akayi amfani da LEFT JOIN yana kawo records na duk Data din da take a Table1 naka da kuma Data din da take da alaka da Table1 din from Table2.

Kamar Misali,

Table1 yana dauke da Data na, NIN, STATE, LGA (na mutun 20)

Table2 yana dauke da Data na, BVN, Account Number, NIN, FullName (mutun 40)

To idan mukayi amfani da LEFT JOIN, zai kawo mana records na duk Data da take a Table1 (na mutun 20), sannan ya kawo mana records na Data da take da alaka da Table1 daga Table2 wadanda sukayi dai dai da column da mukayi amfani da shi a matsayin Column da yake a cikin wadannan Tables namu guda biyu.

Anan, zamu ga Records na mutun 20 daga Table1 duka, maybe sai muga Records na mutun 10 daga Table2 cikin mutun 40 da muke dasu, idan har sune kawai muke dasu masu alaka da Tables din guda biyu.

Ga Yadda ake rubuta Query na LEFT JOIN a SQL:

SELECT (ananzakayi selecting columns da kake nema, ko kake so Query naka ya kawo mka)
FROM (anan zaka rubuta sunan Table1 naka, ko duk table din da yake dauke da main data)
LEFT JOIN (anan zaka rubuta sunan Table2 naka)
ON (anan zaka rubuta sunan Table1 naka da Table2 hade da sunan Column din da yake a cikinsu baki daya, kamar a misalilin mu yanzu NIN column)

Ga Yadda zamu rubuta LEFT JOIN don ganin duka records din da muke da su a Table1 da kuma wadanda suke da alaka da su daga Table2.

SELECT STATE, BVN
FROM Table1
LEFT JOIN Table2
ON Table1.NIN = Table2.NIN

Anan zai kawo mana duka records na State da BVN numbers da muke da su guda 20 a Table1, sannan ya kawo mana only reocrds din da suke da alaka da wadannan records na Table1 daga Table2 (Na bada misali nace lets say 10 out of 40 da muke dasu).

To anan, sauran 10 records din da babu Data nasu a Table2, tunda 20 Records garemu a Table1, SQL zai rubuta musu NULL duka a wurin.

Zan ci gaba insha Allah, Videos na practicals duka suna nan tafe a karkashin series nawa na KOYI SQL.

Stay blessed.

Ahmad Aminu Ahmad esq.
+2347066309565
ahmadaminuahmad@gmail.com

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