We can filter our duplicate data returned from our database tables. In this video, learn how you can use the DISTINCT SQL keyword to filter our duplicate values from your data set.
- [Narrator] We can use the distinct keyword…as part of your sequel query to filter out duplicate rows.…Let's start with a very simple query.…Let's say we want to see all of the…distinct department id values…that we have in our employees table.…Simply typing select department id from employees…and running the query,…produced us with a list of all department id values…we see a lot of duplicates.…
As you can see, for example,…department id 50 repeats multiple times.…That's because each department has multiple employees…assigned to that department.…For example, department id 50…has multiple employees assigned to it,…so we see this value repeats multiple time in our query,…not a very convenient way…to see all of the distinct department id values…we have in our employees table.…We can fix that by simply adding the distinct keyword…between our select keyword and the list of table columns.…
Using distinct as part of our sequel query…will filter out any duplicate values in the data…that is presented by the sequel query itself.…
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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