MySQL is easy to use, yet extremely powerful, fast, secure, and scalable. MySQL runs on a wide range of operating systems, including UNIX or Linux, Microsoft Windows, Apple Mac OS X, and others. MySQL supports standard SQL (Structured Query Language). MySQL is ideal database solution for both small and large applications. This chapter describes how to obtain and install MySQL. A summary of the procedure follows and later sections provide the details. If you plan to upgrade an existing version of MySQL to a newer version rather than install MySQL for the first time, see Section 2.11, “Upgrading MySQL”, for information about upgrade procedures and about issues that you should consider before upgrading.
Which Java package do I need? Software Developers: JDK (Java SE Development Kit): For Java Developers. Includes a complete JRE plus tools for developing, debugging, and monitoring Java applications. Administrators running applications on a server: Server JRE (Server Java Runtime Environment): For deploying Java applications on servers. Java 6 runtime mac mojave.
The following is an example walkthrough of importing an Excel document into a MySQL database. To run this tutorial you will need an Excel file, and admin access to a running MySQL instance.
For the example we’ll be using the following Excel file on rental boats:
Open your Excel file and click Save As. Choose to save it as a .CSV (Comma Separated) file. If you are running Excel on a Mac, you will need to save the file as a Windows Comma Separated (.csv) or CSV (Windows) to maintain the correct formatting.
- Log into your MySQL shell and create a database. For this example the database will be named
boatdb. Note that the
--local-infileoption is needed by some versions of MySQL for the data loading we’ll do in the following steps.
- Next we’ll define the schema for our
boattable using the
CREATE TABLEcommand. For more details, see the MySQL documentation.
- Run show tables to verify that your table was created.
- Now that there is a database and a table setup, the data can be imported with the
If you are a Chartio user, you can now connect the MySQL database to Chartio and chart away.
Summary: in this tutorial, you will learn how to find duplicate values of one or more columns in MySQL.
Data duplication happens because of many reasons. Finding duplicate values is one of the important tasks that you must deal with when working with the databases.
Setting up a sample table
First, create a table named
contacts with four columns:
Second, inserts rows into the
Third, query data from the contacts table:
contacts table, we have some rows that have duplicate values in the
Find duplicate values in one column
The find duplicate values in on one column of a table, you use follow these steps:
- First, use the
GROUP BYclause to group all rows by the target column, which is the column that you want to check duplicate.
- Then, use the
COUNT()function in the
HAVINGclause to check if any group have more than 1 element. These groups are duplicate.
The following query illustrates the idea:
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By using this query template, you can to find rows that have duplicate emails in the
contacts table as follows:
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This picture shows the output of the query that shows the duplicate emails:
Find duplicate values in multiple columns
Sometimes, you want to find duplicate rows based on multiple columns instead of one. In this case, you can use the following query:
Rows are considered duplicate only when the combination of columns are duplicate therefore we used the
AND operator in the
Mysql Workbench Tutorial Mac
For example, to find rows in the
contacts table with duplicate values in
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The following illustrates the output of the query:
Mysql Workbench Mac Tutorial
In this tutorial, you have learned how to find duplicate rows based on value of one or more columns in MySQL.