Recap

Commands

You have already learned a lot about writing code in SQL! Let's take a moment to recap all that we have covered before moving on:

Statement	How to Use It	Other Details
SELECT	SELECT Col1, Col2, …	Provide the columns you want
FROM	FROM Table	Provide the table where the columns exist
LIMIT	LIMIT 10	Limits based number of rows returned
ORDER BY	ORDER BY Col	Orders table based on the column. Used with DESC.
WHERE	WHERE Col > 5	A conditional statement to filter your results
LIKE	WHERE Col LIKE '%me%'	Only pulls rows where column has 'me' within the text
IN	WHERE Col IN ('Y', 'N')	A filter for only rows with column of 'Y' or 'N'
NOT	WHERE Col NOT IN ('Y', 'N')	NOT is frequently used with LIKE and IN
AND	WHERE Col1 > 5 AND Col2 < 3	Filter rows where two or more conditions must be true
OR	WHERE Col1 > 5 OR Col2 < 3	Filter rows where at least one condition must be true
BETWEEN	WHERE Col BETWEEN 3 AND 5	Often easier syntax than using an AND

Other Tips

Though SQL is not case sensitive (it doesn't care if you write your statements as all uppercase or lowercase), we discussed some best practices. The order of the key words does matter! Using what you know so far, you will want to write your statements as:

SELECT col1, col2
FROM table1
WHERE col3  > 5 AND col4 LIKE '%os%'
ORDER BY col5
LIMIT 10;

Notice, you can retrieve different columns than those being used in the ORDER BY and WHERE statements. Assuming all of these column names existed in this way (col1, col2, col3, col4, col5) within a table called table1, this query would run just fine.

Looking Ahead

In the next lesson, you will be learning about JOINs. This is the real secret (well not really a secret) behind the success of SQL as a language. JOINs allow us to combine multiple tables together. All of the operations we learned here will still be important moving forward, but we will be able to answer much more complex questions by combining information from multiple tables! You have already mastered so much - potentially writing your first code ever, but it is about to get so much better!