12 laboratoriya ishi mavzu: Bir nеchta jadvallar birlashtirish, joinlar bilan ishlash Ish

12.4 – rasm. Full outer join operatorining Venn diagrammasi orqali ko’rinishi

Ishni bajarish tartibi

1. 
   SQL INNER JOIN operatori
   

So`rov: SELECT *FROM Xodimlar
INNER JOIN Xodimlar2
ON Xodimlar.fish=Xodimlar2.fish;
Natija:

2. LEFT JOIN operatori
So`rov:
SELECT *FROM Xodimlar
LEFT JOIN Xodimlar2
ON Xodimlar.kon_id=Xodimlar2.kon_id;
Natija:

3. CROSS JOIN operatori
So`rov:
SELECT *FROM Xodimlar
CROSS JOIN Xodimlar2
ON Xodimlar.maoshi=Xodimlar2.maoshi;
Natija:


13 - LABORATORIYA ISHI
Mavzu: Murakkab so‘rovlar yaratish. TOP, LIMIT yoki ROWNUM

Ishdan maqsad: Berilgan predmet soha ma`lumotlar bazasidan foydalanib TOP, LIMIT yoki ROWNUM lardan foydalanishni o`rganish.
Masalani qo`yilishi: Predmet soha ma`lumotlar bazasi shakllantirilgandan so`ng undan unumli foydalanishni tashkil etish maqsadida TOP, LIMIT yoki ROWNUM lar orqali so`rovlar yaratish.
Uslubiy ko`rsatmalar: SQL LIMIT va SQL TOP operatorlarining vazifasi belgilangan satrlarni chaqirishdan iborat. SQL TOP operatori MS SQL Serverda ishlaydi, SQL LIMIT operatori esa MySQLda va Oracle da ROWNUM operatori ishlaydi ularnig vazifasi bir hil.
SQL Server / MS Access Syntax:
SELECT TOP number|percent column_name(s)
FROM table_name
WHERE condition;
MySQL Syntax:
SELECT column_name(s)
FROM table_name
WHERE condition
LIMIT number;
Oracle Syntax:
SELECT column_name(s)
FROM table_name
WHERE ROWNUM <= number;