Learn about the function of LEFT JOINS in SQL and how to perform them.
- [Instructor] The left join in the SQL language…is used to return all rows from the left table,…that is, the employees tables in our case,…as well as matched rows from the right table,…that is the departments table in our case.…In order to run a left join, you simply type…left join as part of the front clause of your SQL command.…So for example, you can select your data from employees,…left join on departments.…In this case, we will retrieve all records…from the employees tables, as well as matching records…from the department tables.…
However, there might be null values returned…from the departments table,…because if no matching rows exist…between employees and departments,…we will still get these rows from the employees table.…That's because we are running a left join.…So enough talk, let's see left joins in action.…We can actually use the same exact SQL query…from our previous video, with one small modification.…We change inner join to left join.…
Let's execute this query and see that we got our data back.…
Note: This training course is appropriate for beginning database developers with no prior experience with SQL or Oracle.
- Using Oracle SQL*Developer, the free development environment
- Selecting data from tables
- Filtering data
- Using functions to manipulate data
- Joining data from tables
- Creating tables
- Updating values
- Truncating data
- Grouping and ordering result sets
- Working with primary keys
- Checking constraints
Skill Level Beginner
Database Foundations: Core Conceptswith Adam Wilbert2h 14m Beginner
Database Foundations: Administrationwith Adam Wilbert1h 14m Beginner
Oracle 12c Database: Administrationwith David Yahalom3h 58m Beginner
1. Introduction to SQL
2. Preparing the Course Environment
Downloading the course VM2m 16s
3. Using Oracle SQL Developer
4. Basic SELECT Queries
5. String, Number, and Date Functions
6. Joining Table Data
7. Manipulating Data
8. Grouping Data
9. Advanced Topics
Next steps1m 33s
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