Examining the Differences Between Two MySQL Tables

A MySQL database, which stores and organizes data in a structured format, is built on MySQL tables. In this tutorial, we'll demonstrate how to compare two MySQL tables using the GUI and CLI tools for MySQL. You should be aware that comparing MySQL tables is critical for ensuring data consistency, spotting discrepancies, and catching data migration errors. We'll also point out important elements to take into account when comparing tables.

Method 1: Using MySQL's Command Line Interface

You must first launch the application and enter your password to access the MySQL server before using the MySQL command line interface. After completing this, you can connect with the server using the client.

Table comparisons in MySQL

Step 1: Preparing the stage

In order to compare two tables, we must first create them in MySQL. Call them "orders" and "orders2," respectively. The same columns, like "id," "order date," and "amount," will be present in both tables.

Step 2: Filling up the tables

It's time to update our tables with some new information. We'll insert values like "id," "order date," and "amount" into the "orders" table using the "insert into" command. The "orders2" table will receive the same treatment.

mysql> create table orders(id int, order_date date, amount int);

mysql> insert into orders(id, order_date, amount)

     values(1,'2020-07-25',250),

     (2,'2020-07-26',350),

     (3,'2020-07-27',200),

     (4,'2020-07-28',150);

mysql> create table orders2(id int, order_date date, amount int);

mysql> insert into orders2(id, order_date, amount)

     values(3,'2020-07-27',200),

     (4,'2020-07-28',150),

     (5,'2020-07-29',250),

     (6,'2020-07-30',300);

Step 3: The comparing starts now!

It's time to compare the two tables at about this point. We'll compare columns from various tables using the "select" command. The "id" columns from the "orders" and "orders2" tables, for instance, can be compared.

We'll use the "where" and "in" keywords in the query to only choose records that match. "Select * from orders where id in (select id from orders2)," for instance.

mysql> select * from orders

       where id in

       (select id from orders2);

We'll place a "NOT" keyword in the query before the "IN" keyword to choose only records that do not match.

mysql> select * from orders

            where id NOT in

            (select id from orders2);

Step 4: Matching records revealed

Finally, we'll combine the data from both tables while keeping duplicate rows by using the "union all" command. "Select id, order date, amount from orders union all select id, order date, amount from orders2," as an illustration.

Then, to locate records with a count higher than 1, we'll use the "group by" and "having" commands. As a result, records that appear more than once will be identified as a match.

mysql> select id, order_date, amount

       from (

           select id, order_date, amount

           from orders

           union all

           select id, order_date, amount

           from orders2)

       temp

       group by id, order_date, amount

       having count(*) > 1;

You can use MySQL to compare two tables and find matching records by following these easy steps.

Method 2: Using a MySQL GUI tool

In MySQL, you can use a graphical user interface (GUI) tool when you need to compare MySQL tables. The best tool for you should be chosen because they all have different features. Popular choices comprise:

MySQL Workbench

This is a well-known MySQL management tool with a feature for comparing data. You can use it to compare and synchronize the data in two MySQL databases, as well as to create SQL scripts that will update one database to reflect the data in the other. Additionally, it provides a wide range of functionalities, including visual data modeling, SQL development, server administration, and many more.

SQL Delta

You can use this tool to compare and synchronize the data and structure of two MySQL databases. Additionally, it includes an integrated SQL editor and a function for creating SQL scripts to update one database to match the other. Additionally, it supports various MySQL versions, permits comparison, and synchronizes both data and schema. It also has a feature that lets you compare and synchronize data across various database servers, as well as one that lets you create a detailed report of the comparison.

DBComparer

Two MySQL databases can be compared and their data synchronized using this tool. It supports various MySQL versions and compares and synchronizes data and schema. Additionally, it has a function for creating SQL scripts that will update one database to match the other. Additionally, it has a feature that lets you create a thorough report of the comparison and can compare and synchronize data for various database servers, just like SQL Delta.

Using dbForge Studio for MySQL 

Here are detailed instructions on how to compare data between two tables using dbForge Studio for MySQL:

1. Open dbForge Studio for MySQL Server.

1. Click on Comparison > New Data Comparison.
2. Choose the type of connections for the Source and Target in the New Data Comparison wizard. The words "Database" and "Scripts Folder" are available.
3. For the "Database" type, choose the SQL Server connection and specific database you want to compare from the drop-down list. If you need to create a new connection, click "Manage..." and enter the necessary details.
4. Choose the specific folder you want to compare for the "Scripts Folder" type by clicking it, or click "Browse" to locate it. Click "New" and enter the required information if you need to create a new scripts folder.
5. To compare the data, click the "Compare" button. To access additional wizard pages and customize the comparison, click "Next."

A synchronization script will be made in order to compare and synchronize script folders. This script can be opened in an internal browser or saved to a file. You have the choice to update the scripts folder following synchronization if a scripts folder is chosen as the Target.

1. When using a scripts folder as a data source, take into account turning on the "Ignore spaces in object names" and "Ignore trailing spaces" options.

It should be noted that when using a scripts folder as the target data source, table definition comments will be lost if the table is changed after the object creation script has been updated.

When using a scripts folder as a data source, it's also a good idea to enable the options to ignore spaces in object names and ignore trailing spaces. This is due to the possibility that white space and comments at the beginning and end of an object definition, such as views, stored procedures, and rules, may not always be handled correctly by MySQL Server. You can use all of these to locate every MySQL data diff and MySQL table diff present in databases

Summary

The core of a MySQL database is a set of tables. With the help of the MySQL Command Line Interface and GUI tools, we've demonstrated how to compare two MySQL tables in this guide. To help you compare them, we've highlighted important factors.