What are some common aggregate functions and how do they work? Here are some common aggregate functions.
- [Instructor] SQL provides a number of functions … that operate on aggregate values. … Here, we're using the world database, … and you've seen this query a number of times, … SELECT COUNT with an asterisk from a table. … So when I execute that, … we get a count of all the rows in the Country table. … The asterisk parameter is actually a special case … for counting all the rows in a table. … If you provide a column name, … counts only the non null values in that column, … and in this case, you see we get a smaller number, 232. … The average function, AVG for average, … returns the average value for a column of numerical values. … And here we have the average of all the population values … for every country ain the Country table. … You can of course use the GROUP BY clause … with any of the aggregate functions. … And so, here we have average population grouped by region. … MIN and MAX functions will give you … the minimum value and a maximum value from a set of values. … And the SUM function will sum …
This course was created by Bill Weinman. We are pleased to offer this training in our library.
- How databases are organized
- Selecting rows and columns
- Creating new tables
- Inserting and updating data
- Sorting and filtering
- Accessing related tables with JOIN
- Working with strings
- Understanding numeric types
- Using aggregate functions and transactions
- Automating data with triggers
- Creating views
- Using CRUD functions
Skill Level Beginner
2. SQL Overview
3. Fundamental Concepts
7. Dates and Times
Dates and times2m 6s
11. Views and Subselects
12. A Simple CRUD Application
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