﻿ SQL: Find the last name of all employees, without duplicates - w3resource

# SQL: Find the last name of all employees, without duplicates

## SQL Basic Select Statement: Exercise-31 with Solution.

From the following table, write a SQL query to find the unique last name of all employees. Return emp_lname.

Sample table: emp_details

Sample Solution:

``````SELECT DISTINCT emp_lname
FROM emp_details;
``````

Output of the Query:

```emp_lname
Saule
Robbin
Sitaraman
Mardy
Foster
Emily
Manuel
Dosio
Gabriel
Snappy
Snares
Dosni
```

Relational Algebra Expression:

Relational Algebra Tree:

## Query Visualization:

Duration:

Rows:

Cost:

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## SQL: Tips of the Day

Nested select statement in SQL Server.

You need to alias the subquery.

```SELECT name FROM (SELECT name FROM agentinformation) a
```

or to be more explicit

```SELECT a.name FROM (SELECT name FROM agentinformation) a
```

Database: SQL Server

Ref: https://bit.ly/3Qruiu5