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.