MySQL query to count the duplicate ID values and display the result in a separate column

To count the duplicate ID values, use aggregate function COUNT() and GROUP BY. Let us first create a table −

mysql> create table DemoTable
(
   Id int,
   Name varchar(100)
);
Query OK, 0 rows affected (1.30 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values(50,'Chris');
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable values(51,'David');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values(51,'Mike');
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable values(50,'Sam');
Query OK, 1 row affected (0.17 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+------+-------+
| Id   | Name  |
+------+-------+
|   50 | Chris |
|   51 | David |
|   51 | Mike  |
|   50 | Sam   |
+------+-------+
4 rows in set (0.00 sec)

Following is the query to display the count of duplicate ID values in a new column −

mysql> select Id,count(Name) as Count
   from DemoTable
   group by Id;

This will produce the following output −

+------+-------+
| Id   | Count |
+------+-------+
|   50 |     2 |
|   51 |     2 |
+------+-------+
2 rows in set (0.00 sec)

AmitDiwan

Published on 01-Oct-2019 07:47:13

• Related Questions & Answers
• Count duplicate ids and display the result in a separate column with MySQL
• MySQL query to count occurrences of distinct values and display the result in a new column?
• Display the count of duplicate records from a column in MySQL and order the result
• MySQL query to find duplicate tuples and display the count?
• MySQL query to group results by date and display the count of duplicate values?
• Concatenate the column values with separate text in MySQL and display in a single column
• MySQL query to count number of duplicate values in a table column
• MySQL query to display the first alphabet from strings in a separate column
• MySQL query to display the count of distinct records from a column with duplicate records
• Get the minimum and maximum value from a VARCHAR column and display the result in separate MySQL columns?
• Query to divide the values of two columns and display the result in a new column using MySQL wildcard?
• Setting column values as column names in the MySQL query result?
• MySQL query to get the count of values and display the count in a new column ordered in descending order
• How to concatenate columns based on corresponding duplicate id values in MySQL? Display the duplicate values in the same column separated by slash
• How to round MySQL column with float values and display the result in a new column?