Database query ek request hai jo database management system (DBMS) se specific data ko retrieve, modify, insert, ya delete karne ke liye ki jaati hai. Database query programming language (jaise ki SQL) ka istemal karke likhi jaati hai aur database ke schema aur data ke sath interact karne ke liye use hoti hai.
Database queries ko execute karne ke liye, developers SQL (Structured Query Language) ya kisi aur query language ka istemal karte hain jo specific DBMS ke liye designed hota hai.
Kuch common operations jo database queries ke through perform kiye jaate hain wo hai yah:
1. Data Retrieval: Queries ka istemal data retrieve karne ke liye hota hai. SELECT statement ka istemal hota hai data ko specific columns aur rows mein retrieve karne ke liye.
2. Data Modification: Database queries ko istemal karke data ko modify kiya ja sakta hai. INSERT, UPDATE, aur DELETE statements ka istemal hota hai data ko add, update, aur delete karne ke liye.
3. Data Filtering: Queries ka istemal data ko filter karne ke liye hota hai. WHERE clause ka istemal hota hai specific criteria ke base par data ko filter karne ke liye.
4. Data Sorting: Queries ka istemal data ko sort karne ke liye hota hai. ORDER BY clause ka istemal hota hai data ko ascending ya descending order mein sort karne ke liye.
5. Data Aggregation: Queries ka istemal data ko aggregate karne ke liye hota hai. Aggregation functions jaise ki SUM, AVG, MIN, MAX ka istemal hota hai data ko summarise karne ke liye.
Database queries ka istemal web applications, mobile apps, aur other software applications mein hota hai data access aur manipulation ke liye. Queries ko execute karne ke baad, DBMS specific data ko retrieve karta hai aur application ko desired results provide karta hai.
