How can i count duplicate records in mysql?

Asked By: Stephen Denesik
Date created: Thu, Jun 24, 2021 5:59 PM
Best answers
Answered By: Thelma Tromp
Date created: Fri, Jun 25, 2021 1:12 AM
Find Duplicate Row values in One Column

SELECT col, COUNT(col) FROM table_name GROUP BY col HAVING COUNT(col) > 1; In the above query, we do a GROUP BY for the column for which we want to check duplicates. We also use a COUNT() and HAVING clause to get the row counts for each group.

How do i check mysql version?

  1. Check MySQL Version with V Command. The easiest way to find the MySQL version is with the command: mysql -V…
  2. How to Find Version Number with mysql Command. The MySQL command-line client is a simple SQL shell with input editing capabilities…
  4. SELECT VERSION Statement…
  5. STATUS Command.

How do i check mysql version?


How do i open a mysql database?

  1. Open the MySQL command line.
  2. Type the path of your mysql bin directory and press Enter.
  3. Paste your SQL file inside the bin folder of mysql server.
  4. Create a database in MySQL.
  5. Use that particular database where you want to import the SQL file.
  6. Type source databasefilename.sql and Enter.
  7. Your SQL file upload successfully.


How do i access mysql client?

Launch the MySQL Command-Line Client. To launch the client, enter the following command in a Command Prompt window: mysql -u root -p . The -p option is needed only if a root password is defined for MySQL. Enter the password when prompted.

How do i access mysql client?


How to connect online mysql database in c?

  • Access MySQL database from C Program To access MySQL database, you need to have the mysql-devel package on you system. This package provides the share libraries and header files required to MySQL client program development. Header files are required for program compilation and shared libraries are used at run-time.


How do i get a list of databases in mysql?

The most common way to get a list of the MySQL databases is by using the mysql client to connect to the MySQL server and run the SHOW DATABASES command. If you haven't set a password for your MySQL user you can omit the -p switch.

How do i get a list of databases in mysql?


How do i run a mysql database?

  1. Download and install a MySQL server and MySQL Connector/ODBC (which contains the Unicode driver)…
  2. Configure the database server for use with Media Server: ...
  3. Add the MySQL bin directory path to the PATH environmental variable…
  4. Open the mysql command line tool:


How can i see the tables in mysql database?

Show MySQL Tables

To get a list of the tables in a MySQL database, use the mysql client tool to connect to the MySQL server and run the SHOW TABLES command. The optional FULL modifier will show the table type as a second output column.

How can i see the tables in mysql database?

62 Related questions

We've handpicked 62 related questions for you, similar to «How can i count duplicate records in mysql?» so you can surely find the answer!

What is mysql in web application?

MySQL is a popular open source database management system commonly used in web applications due to its speed, flexibility and reliability. MySQL employs SQL, or Structured Query Language, for accessing and processing data contained in databases.

How do i find mysql hostname and port?

4 Answers. The SQL query SHOW VARIABLES WHERE Variable_name = 'hostname' will show you the hostname of the MySQL server which you can easily resolve to its IP address. SHOW VARIABLES WHERE Variable_name = 'port' Will give you the port number.

How to import csv data in mysql table?

Here are the steps: Prepare the CSV file to have the fields in the same order as the MySQL table fields. Remove the header row from the CSV (if any), so that only the data is in the file. Go to the phpMyAdmin interface. Select the table in the left menu. Click the import button at the top. Browse to the CSV file.

How to check hostname for mysql?

The SQL query SHOW VARIABLES WHERE Variable_name = 'hostname' will show you the hostname of the MySQL server which you can easily resolve to its IP address. SHOW VARIABLES WHERE Variable_name = 'port' Will give you the port number.

How do i view data in mysql?

Find data across a MySQL connection by using the text search feature on any number of tables and schemas. From the schema tree, select the tables, schemas, or both to search and then right-click the highlighted items and click Search Data Table from the context menu.

How to access mysql database windows?

Enter mysql.exe -uroot -p , and MySQL will launch using the root user. MySQL will prompt you for your password. Enter the password from the user account you specified with the –u tag, and you'll connect to the MySQL server.

What is varchar in mysql?

Varchar in MySQL is a data type used for storing text whose length can have a maximum of 65535 characters. The varchar columns in the table are of variable length string that can hold either numeric or character or both.

How do i connect to a mysql database?

Click Services tab. Expand the Drivers node from the Database Explorer.... Enter User Name and Password.... Click OK to accept the credentials.... Click OK to accept the default schema. Right-click the MySQL Database URL in the Services window (Ctrl-5).

What is a mysql view?

A view is a database object that has no values. Its contents are based on the base table. It contains rows and columns similar to the real table. In MySQL, the View is a virtual table created by a query by joining one or more tables.

Where are mysql tables stored ubuntu?

By default, the datadir is set to /var/lib/mysql in the /etc/mysql/mysql.

How do i connect to mysql locally?

Locate the MySQL Command-Line Client.... Run the client.... Enter your password.... Get a list of databases.... Create a database.... Select the database you want to use.... Create a table and insert data.... Finish working with the MySQL Command-Line Client.

How to use mysql server in xampp?

XAMPP only offers MySQL (Database Server ) & Apache (Webserver) in one setup and you can manage them with the xampp starter. After the successful installation navigate to your xampp folder and execute the xampp -control.exe Press the start Button at the mysql row. Now you've successfully started mysql.

How can i see all tables in mysql?

To get a list of the tables in a MySQL database, use the mysql client tool to connect to the MySQL server and run the SHOW TABLES command. The optional FULL modifier will show the table type as a second output column.

How to check mysql service is running or not?

Starting MySQL from the Windows Command Line How to Open a Windows Command Prompt Start by opening the Run command box in Windows.... Verify MySQL is Running on Windows Next, run the command to display a list of all the services that are currently running.... Connect to a Local MySQL Server

How can i see the existing database in mysql?

Show MySQL Databases The most common way to get a list of the MySQL databases is by using the mysql client to connect to the MySQL server and run the SHOW DATABASES command. If you haven't set a password for your MySQL user you can omit the -p switch.

How to create one table to another table in mysql?

You can create one table from another by adding a SELECT statement at the end of the CREATE TABLE statement: CREATE TABLE new_tbl [AS] SELECT * FROM orig_tbl; mysql> CREATE TABLE bar (UNIQUE (n)) SELECT n FROM foo; CREATE TABLE foo (a TINYINT NOT NULL) SELECT b+1 AS a FROM bar;

How do i run a mysql query?

You can execute a MySQL query towards a given database by opening the database with phpMyAdmin and then clicking on the SQL tab. A new page will load, where you can provide the desired query. When ready click on Go to perform the execution. The page will refresh and you will see the results from the query you provided.

How do i know if a mysql table is corrupted?

You can find this information in the error log or in information_schema. mysql> select table_name,engine from information_schema. tables where table_name = '<TABLE>' and table_schema = '<DATABASE> ' ; The main tools/commands to diagnose issues with data corruption are CHECK TABLE, REPAIR TABLE, and myisamchk.

Should i learn mysql or postgresql?

In general, PostgreSQL is best suited for systems that require execution of complex queries, or data warehousing and data analysis. MySQL is the first choice for those web-based projects which require a database merely for data transactions and not anything intricate.

How is data in a database stored mysql?

Basically mySQL stores data in files in your hard disk. It stores the files in a specific directory that has the system variable "datadir". Opening a mysql console and running the following command will tell you exactly where the folder is located.

How to download mysql database for linux?

Support Network Install MySQL. Install the MySQL server by using the Ubuntu operating system package manager: sudo apt-get update sudo apt-get install mysql-server.... Allow remote access.... Start the MySQL service.... Launch at reboot.... Configure interfaces.... Start the mysql shell.... Set the root password.... View users.

What is root password in mysql installation?

In MySQL, by default, the username is root and there's no password. If during the installation process, you accidentally put a password in and don't remember, here is how to reset the password: Stop the MySQL server if it is running, then restart it with the –skip-grant-tables option.

How to remove mysql server from linux?

How do I uninstall Mysql server ? Just use the apt-get command as follows remove both MySQL server and client in Ubuntu Linux : sudo apt-get --purge remove mysql -client mysql -server mysql-common sudo apt-get autoremove Sample outputs (pay attention to package names):

How to install mysql client ubuntu?

Installing MySQL on Ubuntu First, update the apt package index by typing: sudo apt update. Then install the MySQL package with the following command: sudo apt install mysql-server. Once the installation is completed, the MySQL service will start automatically.

How to create database in mysql workbench step by step?

Open the MySQL Workbench as an administrator (Right-click, Run as Admin). Click on File>Create Schema to create the database schema. Enter a name for the schema and click Apply. In the Apply SQL Script to Database window, click Apply to run the SQL command that creates the schema.

How do i backup mysql command line?

mysqldump -u [username] –p[password] [database_name] > [dump_file.sql] [username] - A valid MySQL username. [password] - A valid MySQL password for the user. [database_name] - A valid Database name you want to take backup. [dump_file.

How do i install the latest version of mysql on linux?

To install, use the yum command to specify the packages that you want to install. For example: root-shell> yum install mysql mysql-server mysql-libs mysql-server Loaded plugins: presto, refresh-packagekit Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package mysql.

How do i download mysql from the command-line?

To install MySQL Shell on Microsoft Windows using the MSI Installer, do the following: Download the Windows (x86, 64-bit), MSI Installer package from When prompted, click Run. Follow the steps in the Setup Wizard.

How do i find my default mysql port?

13 Answers. You should see a line that looks like this if mysql is indeed listening on that port. Port 3306 is MySql's default port. To connect, you just have to use whatever client you require, such as the basic mysql client.

How to change a row name in mysql?

To rename a column in MySQL the following syntax is used: ALTER TABLE table_name RENAME COLUMN old_column_name TO new_column_name ; This command is used to change the name of a column to a new column name.

How do i download mysql database?

To download MySQL installer, go to the following link There are two installer files: If you are connecting to the internet while installing MySQL, you can choose the online installation version mysql-installer-web-community-<version>.exe.

How to find the root password for mysql?

How to retrieve MySQL root password Log in as root into your server through SSH (eg: puTTY/terminal/bash). Alternatively, run the commands that follow as su or sudo as root user.... Navigate to /etc/mysql /cd /etc/mysql. View the file my. cnf either using the command cat or use any text editing software (vi/vim/nano).

Is mysql better than mongodb?

MongoDB is faster than MySQL due to its ability to handle large amounts of unstructured data when it comes to speed. It uses slave replication, master replication to process vast amounts of unstructured data and offers the freedom to use multiple data types that are better than the rigidity of MySQL.

Is sql server faster than mysql?

For the INSERT operations, MySQL worked faster than SQL Server. For transaction processing, MySQL is fast. With the help of its InnoDB storage engine, MySQL can handle high concurrency for transactions. However, MySQL struggles with reporting workloads, mainly when there are queries that need to join large tables.

How to connect html form to mysql database?

For this you need to follow the following steps: Step 1: Filter your HTML form requirements for your contact us web page.... Step 2: Create a database and a table in MySQL.... Step 3: Create HTML form for connecting to database.... Step 4: Create a PHP page to save data from HTML form to your MySQL database.... Step 5: All done!

Can mysql connect to mariadb?

Summary: in this tutorial, you will learn how to connect to the MariaDB server using the mysql command-line program. To connect to MariaDB, you can use any MariaDB client program with the correct parameters such as hostname, user name, password, and database name.

Is mysql free software?

MySQL is free and open-source software under the terms of the GNU General Public License, and is also available under a variety of proprietary licenses.

Can i insert a negative value mysql?

MySQL MySQLi Database The “unsigned” in MySQL is a data type. Whenever we write an unsigned to any column that means you cannot insert negative numbers. Suppose, for a very large number you can use unsigned type.

Is mysql an open-source operating system?

No, MySQL is an open-source database system

Why use sqlite instead of mysql?

SQLite is meant to be great for both developing and testing and offers more than what is needed for development. On the other hand, MySQL is very easy to work with. For instance, it can be easily installed, third-party tools make it a simple database to get started with, and it's enriched with features.

How to see the users of a database mysql?

To show a list of all users on the MySQL database, query the mysql.user table : Some usernames are repeated, as they have different host values, and possibly different values for other columns. To find a list of usernames only, or a distinct list of users, use the DISTINCT keyword on the user column.

How do you connect db2 and mysql?

Take a shot at adoDB - find it here:

How to show users in mysql using a linux terminal?

Once we have access to our server, we have to enter the MySQL console. To do it, we need root privileges. Enter this into the command line: Then, we will have to type in our MySQL root password. It should be different from the system root password. Once we are in the MySQL console as the root user, we can run sentences and commands.

How do i download mysql 5.7 on ubuntu?

Tutorial MySQL 5.7 - Installation on Ubuntu 20.04 Download and install the MySQL repository package. Select the option UBUNTU BIONIC. On the MySQL Server and Cluster screen, select the option MYSQL-5.7. Verify the configuration summary and click on the OK button.

What is ibd file in mysql?

An IBD file is a MySQL table created by the InnoDB database engine. It contains a table-specific tablespace and index data.... InnoDB is the default database engine that MySQL uses to create, update, and otherwise manage table-based data.

Where can i download and install mysql offline?

If you are connecting to the internet while installing MySQL , you can choose the online installation version mysql -installer-web-community-.exe. In case you want to install MySQL offline, you can download the mysql -installer-community-.exe file.

How do i access my mysql database from another computer?

Log into cPanel and click the Remote MySQL icon under Databases. Type in the connecting IP address, and click the Add Host button.... Click Add, and you should now be able to connect remotely to your database.

How do i manage mysql database in phpmyadmin?

The main functionality of phpMyAdmin is to manage your databases. Click phpMyAdmin under the Databases section in cPanel. On the phpMyAdmin interface, you will see a list of your databases on the left panel. Click on the database you want to manage.

How do i change column name in mysql?

To change a column's definition, use MODIFY or CHANGE clause along with the ALTER command. mysql> ALTER TABLE testalter_tbl MODIFY c CHAR(10); With CHANGE, the syntax is a bit different. After the CHANGE keyword, you name the column you want to change, then specify the new definition, which includes the new name.

How to troubleshoot a problem connecting to mysql?

For additional information if you are unable to connect, see Section 6.2.21, “Troubleshooting Problems Connecting to MySQL”. For a client program to connect to the MySQL server, it must use the proper connection parameters, such as the name of the host where the server is running and the user name and password of your MySQL account.

How do you terminate a query in mysql?

Show processlist; Then review the “Time” field to find the longest running query. Next, run the following command to kill it: kill thread_ID;

Is mysql installed linux?

Debian versions of MySQL packages store the MySQL data in /var/lib/mysql directory by default. You can see this in /etc/mysql/my.... Binaries are installed generally in /usr/bin and /usr/sbin directories.

How to take mysql database backup using mysql workbench?

Connect to the database you want to backup by clicking on it under the MySQL connections.... Click on "Data Export" under the "Management" tab on the left side bar. You will get a list of available databases....

How to add mysql path to bash profile?

You can add: export PATH="/usr/local/mysql/bin:$PATH" into your.bash_profile file and you need to RESTART the terminal or open new tab to check the added path. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question.

Can you import a excel file into mysql workbench?

You cannot import an excel file in MySQL Workbench. That was never possible as it would require to parse the excel file. Instead export your excel file in Excel to CSV and import that in MySQL Workbench. Importing CSV into MySQL via MySQL Workbench is easy.

How do i edit a data table in mysql workbench?

Select table, click right mouse button and choose Alter table... option. It will open a new tab in the main pane (right-hand side of the screen) with the editor. You can edit table description in Comments field on the top (blue rectangle).

What are the basics of mysql?

MySQL 101 – The basics. MySQL is one of the most widely used relational database management systems ( RDBMS ). MySQL is used to manage databases in a wide variety of applications including the integrated web solution known as LAMP (Linux Apache MySQL Perl/PHP/Python). Database management is accomplished in MySQL using Structured Query Language (SQL).

How do i delete mysql connection in visual studio?

When you start Visual Studio for the next time, open the connection node in Server Explorer to establish a connection to the MySQL server again. To modify or delete a connection, use the Server Explorer context menu for the corresponding node.

How to reset autoincrement in mysql mariadb?

In MariaDB , the syntax to reset the AUTO _ INCREMENT column using the ALTER TABLE statement is: ALTER TABLE table_name AUTO _ INCREMENT = value;

How to create a test table in mysql?

How to create a Test Table in MySQL. Go to the Windows Start menu, choose Run, type mysql -u root -p, and press Enter. The program will then prompt you for the password. When the MySQL , Monitor starts, it provides its own prompt. At this prompt ( mysql >), you type commands used to create tables , explain tables , insert data, select data, and so on.

Can you use wpdb instead of mysql in php?

One of the solutions that I can think of is to use $wpdb everywhere instead of the plain mysql functions, however, the code has thousands of queries and replacing all of them would turn out to be a bit problematic as the mysqli _query functions are usually followed by mysqli _fetch, etc.

How to reset auto increment in mysql?

How To Reset MySQL Autoincrement Column Directly Reset Autoincrement Value Alter table syntax provides a way to reset autoincrement column. Take a look at following example.... Truncate Table Truncate table automatically reset the Autoincrement values to 0. TRUNCATE TABLE table_name; Use this with caution.... Drop & Recreate Table