SOQL(Salesforce Object Query Language):

• SOQL is a Salesforce Object Query Language, retrieves the records from the database by using SELECT keyword.
• SOQL is used if we know in which object the data is present.
• In SOQL we can query data from single object and as well as multiple objects that are related to each other.
• We can query on all fields of any datatype.
• We can use SOQL in Triggers and classes.
• We can perform DML operation on query results.

SOSL(Salesforce Object Search Language):

• SOSL is a Salesforce Object Search Language, retrieves the records from the database by using the FIND keyword.
• SOSL is used if we don’t know in which object the data is present.
• We can retrieve multiple objects and field values efficiently when the objects may or may not be related to each other.
• We can query only on fields whose data type is text, phone and Email.
• We can use in classes but not in Triggers.
• We cannot perform DML operation on search result.