Usage of three index for the same table
The index is matching perfect (index column is [id_wt], the other fields are contained, filter for ([aktuellster_stand]=(1) AND [id_wt] IS NOT NULL) which is specified in the WHERE condition too).
But when I do not pass the index hint (second version), it uses three different indexes (including the _uq5) for this table and hash joins them. All three used indexes are filtered for at least ([aktuellster_stand]=(1)) and have one or more output columns as index column.
Any idea, why SQL Server uses 3 indexes instead of just one?