Database Join
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This document discusses different types of joins in SQL including inner, left, right, and full joins. It provides examples of how joins combine data from two tables, a Persons table and Orders table, based on relationships between columns like Person ID. Inner joins return rows when there is a match in both tables. Left and right joins return all rows from the left or right table, even without matches. Full joins return rows when there is a match in either table.
Database Join
- 1. Members 1) Farooq Mian 2) Rukhsana 3) Maryem Table of Contents • Inner Join • Left Join • Right Join • Full Join Topic :- Joins
- 2. Well often tables are related to each other with keys. SQL joins are used to query data from two or more tables, Based a relationship between certain columns in these tables.
- 3. Join : Return rows when there is at least one match in both tables. Left Join : Returns all rows from the left table, even if there are no matches in the right table. Right Join : Returns all rows from the right table, even if there are no matches in the left table. Full Join : Return rows when there is a match in one of the tables.
- 4. Perons Table Orders Table O_id Order_no P_id 1 77895 2 2 44441 3 3 99992 2 4 56789 3 5 113379 1 6 12355 1 P_id LastName FirstName Address City 1 Mian Farooq Shadman Lahore 2 Nawaz Fawad Walton Lahore 3 Mian Ahmed Gulberg Karachi 4 Ali Asad DHA Lahore