One way to be able to read access SQL database, SELECT operator is used

*** references everything from that table**

Think about reading the commands – Select ALL FROM customers

If WHERE is used, then it would be a condition that would take ALL from customers as long as it followed certain parameters such as a particular first or last name or a unique identifier.

UNION refers to combining two fields from multiple tables. In this case PatientID and Lastname from the Table Patient and NurseID and Lastname from the table Nurse.

CROSS JOIN is a Cartesian Product so every row is combined from the first table with the second table based on the conditions specified

JOIN Operations are combined based on the conditions

Example

SELECT*

FROM LeftTable LEFT JOIN RightTable;

Whichever table is stated as the first table is the left table and any stated in the right is the right table. If LEFT JOIN occurs, then all of the table from the left side is included regardless of conditions

RIGHT JOIN would do the same for all of the tables of the right side regardless of conditions