In Oracle, MINUS operator is used to return all rows in the first SELECT statement that are not returned by the second SELECT statement.
Each SELECT statement has a dataset and the MINUS operator returns all documents from the first dataset and then removes all documents from the second dataset.
SELECT expression1, expression2, ... expression_n FROM table1 WHERE conditions MINUS SELECT expression1, expression2, ... expression_n FROM table2 WHERE conditions;
1) expression1, expression2, ... expression_n: It specifies the columns that you want to retrieve.
2) table1, table2: it specifies the tables that you want to retrieve records from.
3) conditions: it specifies the conditions that must be fulfilled for the records to be selected.
This example will return one field with the same datatype from two tables "suppliers" and "order_details".
SELECT supplier_id FROM suppliers MINUS SELECT supplier_id FROM order_details;