If you want details of both tables, then you could have:
List<AllDetails> myObject = tableNames.Join(tableSchool, x => x.sID, s => s.schoolID, ((x, s) => new AllDetails(x, s))).ToList();
where:
public class AllDetails
{
private TableName tabName;
private TableSchool tabSchool;
public AllDetails(TableName tableName, TableSchool tableSchool)
{
//Assign fields here
}
}