Mysql queries different data sets based on different logon roles.

The code values of each role are different. The set that meets the conditions is identified based on the code value of the logon role. Column such as 51.135.24.03 (code value) Role 1 (code value: 51) login, contains 51 second ". all the previous data, the found code set is 51. XXX role 2 (code value: 51.135) login, contains 51.135 third ". "For all the previous data, the found code set is 51.135.XX. now we know the logon code value for each role. how can we use SQL statements to find the correct set?

The code values of each role are different. The set that meets the conditions is identified based on the code value of the logon role.
Column such as 51.135.24.03 (code value)
Role 1 (code value: 51) log on, take all the data that contains 51 before the second ".", and the found code set is 51.XXX
Role 2 (code value: 51.135) logs on, obtains all the data before the third "." of 51.135, and the found code set is 51.135.XX.
Now I know the logon code value of each role. how can I use SQL statements to find a set that meets the requirements?