![]() ![]() INSERT INTO `Employee` VALUES ('Veniam','1','640 Damon Junction\nEast Mathew, NY 68818','3'), INSERT INTO `Employee_Department` VALUES ('Information Technology','1'), Listing Queries for table creation and insertion:ĬREATE TABLE IF NOT EXISTS Employee_Department ( To use the JOINS, we will use 2 tables Employee and Employee_Department with the details below. You can use/refer to a helpful site here in order to generate dummy data for the schema. Types Of MySQL JOIN Sample Data Preparation In the next section, we will discuss different types of Joins that are available in MySQL. JOIN with SELECT SELECT – This is the column conditions which would be used for the JOIN to query and fetch data. Hence, JOIN is always used in conjunction with SELECT, UPDATE, or DELETE statements MySQL JOIN is used to fetch, update or delete data from 2 or more tables against a given condition. ![]() So in a nutshell – EMPLOYEE and EMPLOYEE_DEPARTMENT are linked to each other through the Department_id field, which is acting as a FOREIGN KEY for the EMPLOYEE table and PRIMARY KEY for the EMPLOYEE_DEPARTMENT table.īelow image is a pictorial representation having a relationship between both these tables through means of Foreign Key Constraint MySQL JOIN So in this case, we would refer to the Department by a field Department_id in the EMPLOYEE table and all relevant information related to Department – like Department Info, Department head, etc may be kept as part of the EMPLOYEE_DEPARTMENT table. Hence to reduce those duplications and save on storage, databases are kept in a normalized state. a single table having all the columns, a lot of information for example about the Department would be duplicated as there can be a lot of Employees that are part of the same Department. Let’s try to understand this with the help of an example – Suppose there are 2 tables, EMPLOYEE and EMPLOYEE_DEPARTMENT. In normalized MySQL databases, tables have relationships against common columns through means of key constraints like Foreign keys.
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