SELECT yana dawo da bayani daga tebur guda ko fiye — ita ce hihin tambaya ta SQL da aka fi amfani da ita. Kana bayyana waɗannan ginshikai da kika so da daga waɗannen tebura, sanye da gida, waje da ƙayyadaddun sakamako.
name, email
users;
users;
name full_name
users;
Ka jera ginshikai da za ka dawo daga bayan SELECT (ko * don duka), da teburu daga bayan FROM. Sunan keɓe (AS) yana sake suna ginshiaki a cikin sakamakon.
-- ❌ SELECT * fetches every column — wasteful, fragile (breaks if columns change)
SELECT * FROM users;
-- ✅ select only what you need — less data transferred, clearer intent, more stable
SELECT id, name, email FROM users;
Hala SELECT * yana da amfani don sashen bincike, a cikin ainihin lambar kana zaɓi ginshiaki kacal kaɗan da kike buƙata — yana canja data kaɗan, yana bayyana niyyar, kuma ba zai kasu idan ginshiaken teburu ya canja.
SELECT
name,
price * quantity AS total, -- a calculated column
UPPER(name) AS name_upper, -- a function applied to a column
price * 1.1 AS price_with_tax
FROM orders;
SELECT iya kaɗa magudanar hannuwa da ayyukan, ba kacal ginshiaki masu sauki kawai.
SELECT name -- 5. select columns (runs near-last logically)
FROM users -- 1. from the table
WHERE active = true -- 2. filter rows
GROUP BY country -- 3. group
HAVING COUNT(*) > 5 -- 4. filter groups
ORDER BY name -- 6. sort
LIMIT 10; -- 7. limit
LOGICAL execution order (NOT the written order):
FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY → LIMIT
→ This is why you can't use a SELECT alias in WHERE (WHERE runs before SELECT).
SELECT ita ce tushe na bubuƙa bayani — hihin tambaya ta SQL da aka fi amfani da ita, tsakiya ga karanta daga kowane tebur mai dangantaka, don haka sani da kyau shine alhakin kowacce rana.
Fahimtar yadda ake warwareta ginshiaki, amfani da sunan keɓe, da kaɗa magudanar hannuwa yana rufe mahimman karatu na dawo da haraji bayani.
Alhakin gida ne gida SELECT * a cikin lambar aikace (zaɓin kacal ginshiaki waɗanda aka buƙata yana canja data kaɗan, yana fi bayyana, kuma yana ƙarfi sosai ga canja mahala — alhakin gida da aka kara sani).
Abukan gida ga fahimta shine tsarin aiki na halayi na tambaya (FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY → LIMIT), wanda ya bambanta da tsarin rubutacciyya kuma yana bayyana ainihin halaye — kamar yakamata ka aiki SELECT alibi a WHERE bandi (saboda WHERE aiki a hali kafin SELECT).
Wanne mahimmin fahimta yadda tambayoyin suka aiki ainihin shine tushe ga rubutu na daidai tambayoyi da bincike-binciken kuɗodi masu rikici.
Tun kamar karanta bayani da SELECT shine mafi yawa aiki na tebur, kuma tun fahimta zaɓin ginshiaki, sunan keɓe, magudanar hannuwa, kuma musamman tsarin aiki na halayi na tambaya shine tushe ga duka bubuƙa, sani da yare don duk waɗa da suka yi aiki da tebur, sani da kyau na SELECT statement shine gida, kula da aiki na ilmu don duk waɗa da suke aiki da tebur SQL.