SOQL (Salesforce Object Query Language) and SOSL (Salesforce Object Search Language) are both query languages in Salesforce, but they are used for different purposes:

Purpose: SOQL is used to search for and retrieve data from a single object or multiple objects that are related to each other, while SOSL is used to search for data across multiple objects.

Syntax: SOQL has a syntax that is similar to SQL, while SOSL has a syntax that is specific to Salesforce.

Data Retrieval: SOQL retrieves data from a specific set of fields for one or more records, while SOSL retrieves the Ids of records that match the search criteria, and then you can use the Ids to retrieve the data from the specific fields.

Search Scope: SOQL searches only within the database of a single Salesforce instance, while SOSL can search across multiple Salesforce instances, such as when you are using Salesforce across multiple organizations.

In summary, if you need to search for data within a specific object or set of related objects, use SOQL. If you need to search across multiple objects, use SOSL.