Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Find all users with a unique last name in MySQL?
To find all users with unique last name, use GROUP BY HAVING COUNT().
Let us create a table −
Example
mysql> create table demo76 -> ( -> firstName varchar(20), -> lastName varchar(20) -> ); Query OK, 0 rows affected (9.29
Insert some records into the table with the help of insert command −
Example
mysql> insert into demo76 values('John','Doe');
Query OK, 1 row affected (2.52
mysql> insert into demo76 values('David','Smith');
Query OK, 1 row affected (6.31
mysql> insert into demo76 values('Adam','Smith');
Query OK, 1 row affected (1.52Display records from the table using select statement −
Example
mysql> select *from demo76;
This will produce the following output −
Output
+-----------+----------+
| firstName | lastName |+-----------+----------+
| John | Doe || David | Smith |
| Adam | Smith |+-----------+----------+
3 rows in set (0.00 sec)
Following is the query to find all users with a unique last name −
Example
mysql> select max(tbl.firstName), tbl.lastName, -> count(distinct tbl.firstName) as CountOfFirstName -> from demo76 as tbl -> group by tbl.lastName -> having count(distinct tbl.firstName) = 1;
This will produce the following output −
Output
+--------------------+----------+------------------+
| max(tbl.firstName) | lastName | CountOfFirstName |+--------------------+----------+------------------+
| John | Doe | 1 |+--------------------+----------+------------------+
1 row in set (0.00 sec)
Updated on: 11-Dec-2020
394 Views
Advertisements