Practice Session2:31 with Andrew Chalkley
Let's practice the new keywords, operators and functions you've learned in this section.
We've covered a lot in this stage. 0:00 We've been introduced to new keywords, functions, and operators. 0:01 Let's quickly review them and 0:06 then you can practice them in this SQL playground associated with this video. 0:08 Let's start with all the functions you've learned. 0:12 [SOUND] We've used the COUNT function to count the number 0:14 of rows depending on the queries we've created. 0:18 Remember that when giving a specific column name, 0:21 count won't include rows with null values. 0:24 Use a star or asterisk to get all rows. 0:27 The sum function is used to sum all the numeric values in a column. 0:31 We use this to get various totals from the order's table. 0:37 The average function is used to calculate the average values in a given column. 0:41 The maximum and minimum functions are used to compare all values in a column and 0:47 retrieve the minimum and maximum values. 0:52 Finally, we use the round function to round values to a specific decimal place. 0:56 With all of these functions, you can use all of them with all rows in the table or 1:01 a selection of the data you define through a WHERE clause or 1:07 group in sets of rows together. 1:10 This takes us to the keywords you've learned. 1:13 First, we saw the distinct keyword in action. 1:16 This finds unique values in a column. 1:19 Then we use the group by to perform a similar action. 1:22 Find unique values. 1:25 But instead of discarding duplicates, it grouped them together. 1:27 Once the results are grouped, you can use the SQL functions to get 1:32 information about the different groups of rows. 1:36 Finally, if you want to filter based on aggregate information, 1:39 you can't use a where clause. 1:44 You have to use a having clause. 1:45 You were introduced to some new operators by performing math 1:49 on columns of numeric data. 1:52 Addition, subtraction, multiplication, and division. 1:55 Launch the SQL Playground now and you'll find another practice session for you. 2:00 Familiarize yourself with the database schema and 2:05 then proceed to answer questions in each of the coding areas. 2:08 Once you're finished with this session, there's another assessment. 2:15 This section of this course has been pretty challenging. 2:19 And you've accomplished so much. 2:22 You're growing. 2:23 Keep it up. 2:24 In the next section, we'll take a look at some more powerful functions, 2:25 like calculating and formatting dates. 2:28
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