Day 8. Querying Data

Today's lesson is about two of the most important queries in SQL: SELECT and DELETE.

SELECT is the primary means of getting data out of any SQL database. Today's lesson will teach you:

• The fundamentals of a SELECT query

• How to apply conditions for selection with a WHERE clause

• How to control the output of a SELECT query, using DISTINCT, ORDER BY, GROUP BY, and LIMIT

• How to use operators, functions, and aggregating functions within a SELECT

You will also learn some slightly more advanced techniques:

• How to apply further conditions to a resultset with a HAVING clause

• How to output data from a SELECT query into another table or file

• How to do full-text searching

• How to perform subselects, and how to get by without them

Finally, you will learn how to remove data from a table using DELETE.