Mysql Update problem

MySQL & MariaDB Other MySQL® Questions
1

We are noticing that the update statement which was run by the a php code is not happening. The records still reflect default value.
However we do find the update statement logged in bin-log files whihc implies that the update statement was executed successfully in database.

The database engine is INNODB.

What are the scenarios where the entire column value or specific column for few rows gets reset to default value. if any thing triggers this ,where can we trace the cause of the same.

mysql error logs dont show any crash activities.

please help in resolving this mystery!!!

2

Have you tried running the update manually to see how many rows it affects (or at least a SELECT version of it)? If the UPDATE query is running but the data is not changing, then chances are the query is not doing what you think it is doing (i.e. not actually updating any rows, or updating the wrong rows). Most likely this is due to your WHERE clause being incorrect or inconsistent with the data you have.