ORACLE DISTINCT To eliminate the duplicate records from the result set, Oracle DISTINCT clause is used, but only with the SELECT statement.
Syntax:
SELECT DISTINCT columns FROM tables WHERE conditions;
Parameters: columns: It is used to specify the columns to be selected. table_name: It is used to specify the name of the table from which the data needs to be removed. conditions: It is used to specify the conditions to be strictly fulfilled for the action to complete.
Example: Using Distinct Select for single column. Students table:
STUDENT_ID | STUDENT_NAME | STUDENT_AGE |
1 | Joy | 5 |
2 | Smiley | 13 |
3 | Happy | 11 |
Distinct Select Query:
SELECT DISTINCT student_name FROM students WHERE student_id = 2; |
Output:
STUDENT_NAME Smiley
Explanation: The ‘students’ is an already existing table. Here we are trying to specify the distinct name of the student whose ID is equal to 2.
Example: Using Distinct Select for multiple column. Students table:
STUDENT_ID | STUDENT_NAME | STUDENT_AGE |
1 | Joy | 5 |
2 | Smiley | 13 |
3 | Happy | 11 |
Distinct Select Query:
SELECT DISTINCT student_name, student_age FROM students WHERE student_id >= 2; |
Output:
STUDENT_NAME | STUDENT_AGE |
Smiley | 13 |
Happy | 11 |
Explanation: The ‘students’ is an already existing table. Here we are trying to specify the distinct name and age of the students whose student_id is greater than or equal to 2.