The differences are mentioned in the table below:
SOQL vs SOSL
SOQL (Salesforce Object Query Language) SOSL (Salesforce Object Search Language)
Only one object can be searched at a time Many objects can be searched at a time
Can query any type of field Can query only on email, text or phone
Can be used in classes and triggers Can be used in classes, but not triggers
DML Operation can be performed on query results DML Operation cannot be performed on search results
Returns records Returns fields