Channi Studies

A function is a stored program that you can pass a parameters into to return a value. There are lots of functions offered by MySQL that can be found in following reference manual.  MySQL :: MySQL 8.4 Reference Manual :: 14.1 Built-In Function and Operator Reference14.1 Built-In Function and Operator Reference The following table lists each built-in (native) function and operator and provides a s..

A JOIN clause is used to combine rows from two or more tables, based on a related column between them.We will take a look into INNER JOIN, LEFT JOIN, and RIGHT JOIN.  Continued from the previous post, customers table consists of 3 columns: customer_id (PRIMARY KEY), first_name, last_nametransactions table consists of 3 columns: transaction_id (PRIMARY KEY), amount, customer_id (FOREIGN KEY)INSER..

You can think of FOREIGN KEY as a primary key from one table that can be found within a different table.FOREIGN KEY constraint is used to prevent actions that would destory links between tables.Using a FOREIGN KEY, we can establish a link between two tables.  Let's stary by creating a new table for customer data. We will have customer_id, first_name, and last_name columns, and customer_id will b..

AUTO_INCREMENT attribute can be applied to a column that is set as a key. Whenever we insert a new row, the primary key will be populated automatically.  Let's re-create the transactions table that we created before. DROP TABLE transactions; CREATE TABLE transactions( transaction_id INT PRIMARY KEY AUTO_INCREMENT, amount DECIMAL(5, 2)); We can verify AUTO_INCREMENT attribute applied in the..