Channi Studies

We are going to learn about using the logical operators, AND, OR, and NOT. We can combine more than one conditions with those operators. Let's start from the previously built employees table. I want to add a job column into the table. ALTER TABLE employeesADD COLUMN job VARCHAR(25) AFTER hourly_pay;SELECT * FROM employees; I will assign positions to each employee. UPDATE employeesSET job = "..

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..