SELECT [t0].[Id], [t0].[EntityId], [t0].[ParentId]
FROM [Entity] AS [e]
LEFT JOIN (
    SELECT [t].[Id], [t].[EntityId], [t].[ParentId]
    FROM (
        SELECT [e0].[Id], [e0].[EntityId], [e0].[ParentId], ROW_NUMBER() OVER(PARTITION BY [e0].[EntityId] ORDER BY [e0].[Id]) AS [row]
        FROM [Entity] AS [e0]
    ) AS [t]
    WHERE [t].[row] <= 1
) AS [t0] ON [e].[Id] = [t0].[EntityId]