Contents
When do you use the DISTINCT operator in SQL?
Code language: SQL (Structured Query Language) (sql) If you use one column after the DISTINCT operator, the database system uses that column to evaluate duplicate. In case you use two or more columns, the database system will use the combination of value in these columns for the duplication check.
How to retrieve distinct records in SQL Server?
Here we are going to see how to retrieve unique (distinct) records from a Microsoft SQL Server’s database table without using the DISTINCT clause. We will be creating an Employee table in a database called “geeks”. We have the following dup_table table in our geeks database:
How to query for distinct rows in a table?
The set UNION operator can also be used to query for distinct rows in a table: The INTERSECT operator can be used to query for distinct rows in a table: CTE stands for Common Table Expressions. It can also be used to query for distinct rows in a table with the row_number () function as shown below:
What happens when you use distinct in case insensitive?
The first query we run is using case sensitive, so all four rows should show up. All that is different in the next query is the name of the collation. When this query is run using case insensitive, we only get two rows.
How to remove duplicates from a result set in SQL?
The primary key ensures that the table has no duplicate rows. However, when you use the SELECT statement to query a portion of the columns in a table, you may get duplicates. To remove duplicates from a result set, you use the DISTINCT operator in the SELECT clause as follows: SELECT DISTINCT column1, column2, FROM table1;
How does the DISTINCT operator treat null values?
Typically, the DISTINCT operator treats all NULL values the same. As a result, the DISTINCT operator keeps only one NULL value and removes the other from the result set. For example, the following statement returns the distinct phone numbers of employees. Notice that it returned only one NULL value.