Difference between IQueryable and IEnumerable in LINQ

IQueryable: IQueryable represents a query that can be executed against a specific data source, such as a database. When a LINQ query is defined using IQueryable, the query is not executed immediately, but it is deferred until an action is performed, such as iterating over the query results or applying additional operations.

IEnumerable: IEnumerable represents a collection of objects that can be enumerated using a foreach loop. When a LINQ query is defined using IEnumerable, the query is executed immediately and the results are stored in memory. This can be less efficient for working with large datasets compared to IQueryable, which can perform filtering and sorting operations directly on the data source.

Therefore, when working with LINQ queries that involve querying or manipulating data from a database or remote data source, it is generally more efficient to use IQueryable to defer query execution until needed and optimize data retrieval.