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SQL Joins

1. Login in to the mysql client using the login name and password provided by your instructor (if not already logged in). 2. View the existing databases that the MySQL Server is maintaining. SHOW DATABASES; 3. Utilize the photo_album database. USE photo_album; ---- If Need be, recreate the database and load the SQL data in that will be used for this lab CREATE DATABASE photo_album; SOURCE /tmp/photo_album.sql; 4. Query the database to display the active primary customer (email, first and last name) and all the associated active login names associated with that customer. SELECT customers.email_customer, customers.fname, customers.lname, logins.login_name  FROM customers, logins WHERE customers.email_customer = logins.email_customer  AND customers.active_customer = 'True'  AND logins.active_login = 'True';

SQL JOINS

What is a Join? The SELECT queries shown thus far in this training guide retrieve information from a single table at a time. However, not all questions can be answered using just one table. When it's necessary to draw on information that is stored in multiple tables, use a join condition—an operation that produces a result by combining (joining) information in one table with information in another. The contents of two original tables are shown below. These tables can be joined together using a SELECT query which retrieves data from more than one table at a time. table1 table2 +----+----+ | i1 | c1 | +----+----+ | 1 | a | | 2 | b | | 3 | c | +----+----+ 3 rows in set (#.## sec) +----+----+ | i2 | c2 | +----+----+ | 2 | c | | 3 | b | | 4 | a | +----+----+ 3 rows in set (#.## sec) mysql> SELECT * FROM table1 JOIN table2; +----+----+----+----+ | i1 | c1 | i2 | c2 | +----+----+----+----+ | 1 | a | 2 | c | | 2 | b | 2 | c |