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This article "mysql how to judge whether the data exists" article, the sample code introduced in the article is very detailed, has a certain reference value, interested friends must refer to, for "mysql how to judge whether the data exists", Xiaobian sorted out the following knowledge points, please follow the pace of Xiaobian step by step slowly understand, then let us enter the theme.

In mysql, you can use the count() function to determine whether the data exists. The function is used to count the data recorded in the table. The syntax is "select COUNT(field value) as field name from table name where field condition;". The return result is 0. The data does not exist. If the result is greater than 0, it exists.

Operating environment of this tutorial: Windows 10 system, mysql version 8.0.22, Dell G3 computer.

How does MySQL determine if data exists?

Determine whether a record exists or not.

1. Open a query interface

2. The first method uses the count function to obtain the number of records that meet the conditions according to the conditions. If it is equal to 0, it means that there is no record. If it is greater than 0, it means that there is one record.

The count() function is a function used to count records in a table and returns the number of rows matching the condition.

Examples are as follows:

select COUNT(id) as amount from p_user where id=1;

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