remove duplicate records in mysql

MySQL database, often encounter duplicate records, then need to delete duplicate records SQL, the following list of four ways to delete duplicate records, for different situations, I hope to help you. 1, look for redundant records in the table,

Unique query for a single table: distinct unique query for multiple tables: When groupbydistinct is used to query multiple tables, leftjoin is still valid and full join is invalid. when mysql is used, sometimes you need to query records that do not

How does mysql Delete duplicate record statements ?? For example, idnamevalue1app2app3biii4bpp5bpp6cpp7cpp8ciiiid is the primary key required to obtain this result idnamevalue1app3biii4bpp6cpp8ciii method 1 deleteYourTable How does mysql Delete

There are many ways to delete duplicate records. Here I summarize a variety of SQL statements for deleting restart records, such as deleting duplicate id data and searching for duplicate records, remove the smallest record, delete the repeat record,

Although distinct is a syntax for SQL and does not belong to MySQL, here is an example of MySQL.After so many years of distinct, incredibly has been wrong. Always thought that distinct is the removal of duplicate fields, originally it is to remove

single-table only query by: DISTINCTUnique query for multiple tables: Group byDistinct when querying multiple tables, the LEFT join is valid and the full connection is invalid.When using MySQL, it is sometimes necessary to query for a record that

Mysql deletes redundant duplicate records. Sometimes, multiple duplicate records exist in the database. In this case, deduplication is required, that is, only one record is retained... This is especially common in Data Warehouses because of human or

This article mainly introduces the distinct statement in MySQL to query duplicate records and related performance discussions. the point in this article is to avoid using distinct in top-level queries under certain circumstances, for more

In the practical application, often need to implement in a query statement to display more than one table of data, this is called a multiple table data record connection query, referred to the next year will be the query. When you implement a

MySQL deduplication is a common operation. The following describes several common methods for deleting duplicate records in MySQL. If you have encountered any problems in deleting duplicate records in MySQL, take a look. When using mysql, you