SQL: MINUS Query
The SQL MINUS query returns all rows in the first SQL SELECT statement that are not returned in the second SQL SELECT statement.
Each SQL SELECT statement within the SQL MINUS query must have the same number of fields in the result sets with similar data types.
The syntax for the SQL MINUS query is:
select field1, field2, ... field_n from tables MINUS select field1, field2, ... field_n from tables;
SQL MINUS Query - Single field example
The following is an example of an SQL MINUS query that has one field with the same data type:
select supplier_id from suppliers MINUS select supplier_id from orders;
This SQL Minus query example returns all supplier_id values that are in the suppliers table and not in the orders table. What this means is that if a supplier_id value existed in the suppliers table and also existed in the orders table, the supplier_id value would not appear in this result set.
SQL MINUS Query - Using ORDER BY Clause example
The following is an SQL MINUS query that uses an ORDER BY clause:
select supplier_id, supplier_name from suppliers where supplier_id > 2000 MINUS select company_id, company_name from companies where company_id > 1000 ORDER BY 2;
In this SQL MINUS query example, since the column names are different between the two "select" statements, it is more advantageous to reference the columns in the SQL ORDER BY clause by their position in the result set. In this example, we've sorted the results by supplier_name / company_name in ascending order, as denoted by the "ORDER BY 2".
The supplier_name / company_name fields are in position #2 in the result set.