The distinct keyword is used in conjunction with select keyword. It is helpful when there is need of avoiding the duplicate values present in any specific columns/table. When we use distinct keyword only the unique values are fetched.
SELECT DISTINCT column1,column2 FROM table_name column1 , column2: names of the fields of the table table_name: from where we want to fetch This query will return all the unique combination of rows in the table with fields column1 , column2.
NOTE: If distinct keyword is used with multiple columns, the distinct combination is displayed in the result set.
- To fetch unique names from the NAME field
SELECT DISTINCT NAME FROM Student;
NAME Ram RAMESH SUJIT SURESH
- To fetch unique combination of rows from the whole table
SELECT DISTINCT * FROM Student;
ROLL_NO NAME ADDRESS PHONE Age 1 Ram Delhi XXXXXXXXXX 18 2 RAMESH GURGAON XXXXXXXXXX 18 3 SUJIT ROHTAK XXXXXXXXXX 20 4 SURESH Delhi XXXXXXXXXX 18
Please note: Without the keyword distinct in both the above examples 6 records would have been fetched instead of 4, since in the original table there are 6 records with the duplicate values.
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