Two jobs, one with SC and one doesn't need SC

I am working for a company from the last 2 years and I have got SC with this company. I have got another offer which doesn’t need SC. These 2 are full time. I wanted to continue 2 jobs. If I do the 2nd job, can the first one findout about the second one?
Do I need to resign the first job ?

Security clearance holders are normally required to report any changes that would have been reported on the security questionnaire, i.e. employment.

Meaning, you should be reporting your second employment to the clearance sponsoring company/agency.