# MINUS in Oracle

ORACLE MINUS
To return all the rows of the first SELECT statement which are not common to the rows of the second SELECT statement, the Oracle MINUS operator is used. After the subtraction process, the MINUS operator returns the uncommon or unique records from the corresponding rows of the first SELECT statement.

There are however two mandatory conditions for using the MINUS operator in Oracle.

• Each SELECT statement must have the same number of expressions.
• Each corresponding expression in the different SELECT statement should be of the same data type.

Syntax:

SELECT expr_1, expr_2, ... expr_n
FROM table1
WHERE conditions
MINUS
SELECT expr_1, expr_2, ... expr_n
FROM table2
WHERE conditions;


Parameters:

expr_1, expr_2, … expr_n: It is used to specify the columns of the table which needs to be retrieved.
table1, table2: It is used to specify the name of the tables from which the records need to be retrieved.
conditions: It is used to specify the conditions to be strictly followed for selection.

Example 1: Fetching single field from two tables.
Students Table:

 STUDENT_ID NAME AGE 1 Joy 20 2 Smiley 19 3 Happy 21 4 James 22 5 Bond 25

Teachers Table:

 TEACHER_ID NAME AGE 101 James 30 102 Bond 25 103 Smith 40

Query:

SELECT name FROM students MINUS SELECT name FROM teachers;

Output:

NAME
Joy
Smiley
Happy


Explanation:
The ‘students’ and the ‘teachers’ are the already existing tables. After the subtraction, the uncommon or unique rows for the ‘name’ field from the ‘students’ table would appear.

Example 2: Fetching multiple fields from two tables.
Students Table:

 STUDENT_ID NAME AGE 1 Joy 20 2 Smiley 19 3 Happy 21 4 James 22 5 Bond 25

Teachers Table:

 TEACHER_ID NAME AGE 101 James 30 102 Bond 25 103 Smith 40

Query:

SELECT name, age FROM students MINUS SELECT name, age FROM teachers;

Output:

 NAME AGE Joy 20 Smiley 19 Happy 21

Explanation:
The ‘students’ and the ‘teachers’ are the already existing tables. After the subtraction, the uncommon or unique rows for the ‘name’ and the ‘age’ fields from the ‘students’ table would appear.