TempDB Query Top 2 (SQL)

(@P1 numeric(10))INSERT INTO #tt87 WITH(TABLOCK) (_REFFIELDRRef) SELECT
T1._IDRRef
FROM dbo._Reference42 T1
INNER JOIN #tt87 T2 WITH(NOLOCK)
ON T1._ParentIDRRef = T2._REFFIELDRRef
LEFT OUTER JOIN #tt87 T3 WITH(NOLOCK)
ON T1._IDRRef = T3._REFFIELDRRef
WHERE ((T1._Fld595 = @P1)) AND (T3._REFFIELDRRef IS NULL)