I get datetimes with sql but my if-else statement doesn't work

output --> my output

Hi everyone i have a query which is using if else statements with datetime i get datetimes correctly but my if else statement doesn't work i have my code below, i would be glad if you help me thanks.

[1]DECLARE @systemdatetime datetime
SET @systemdatetime=GETDATE()
PRINT @systemdatetime

DECLARE @Tarihvardiya1 datetime
DECLARE @time time
SET @Tarihvardiya1 = convert(date,GETDATE(),120)
SET @Tarihvardiya1=@Tarihvardiya1
PRINT @Tarihvardiya1

DECLARE @Tarihvardiya2 datetime
SET @Tarihvardiya2 = convert(date,GETDATE(),120)
SET @time = '08:00:00'
SET @Tarihvardiya2=@Tarihvardiya2+CAST(@time AS datetime)
PRINT @Tarihvardiya2

DECLARE @Tarihvardiya3 datetime
SET @Tarihvardiya3 = convert(date,GETDATE(),120)
SET @time = '16:00:00'
SET @Tarihvardiya3=@Tarihvardiya3+CAST(@time AS datetime)
PRINT @Tarihvardiya3


/* VARDİYA 1*/
IF (@systemdatetime BETWEEN @Tarihvardiya2 AND @Tarihvardiya3)
BEGIN
print 'vardiya 1'
INSERT INTO snap_table(stok_id,birim_id,Urun_Ismi,Urun_Kodu,Adet,Birim,Tarih) SELECT stok_id,birim_id,Urun_Ismi,Urun_Kodu,Adet,Birim,Tarih FROM stok_durumu WHERE @systemdatetime BETWEEN @Tarihvardiya2 AND @Tarihvardiya3
END

/* VARDİYA 2*/
ELSE IF (@systemdatetime BETWEEN @Tarihvardiya3 AND @Tarihvardiya1)
BEGIN
print 'vardiya 2'
INSERT INTO snap_table(stok_id,birim_id,Urun_Ismi,Urun_Kodu,Adet,Birim,Tarih) SELECT stok_id,birim_id,Urun_Ismi,Urun_Kodu,Adet,Birim,Tarih FROM stok_durumu WHERE @systemdatetime BETWEEN @Tarihvardiya3 AND @Tarihvardiya1
END

/* VARDİYA 3*/
ELSE IF(@systemdatetime BETWEEN @Tarihvardiya1 AND @Tarihvardiya2)
BEGIN
print 'vardiya 3'
INSERT INTO snap_table(stok_id,birim_id,Urun_Ismi,Urun_Kodu,Adet,Birim,Tarih) SELECT stok_id,birim_id,Urun_Ismi,Urun_Kodu,Adet,Birim,Tarih FROM stok_durumu WHERE @systemdatetime BETWEEN @Tarihvardiya1 AND @Tarihvardiya2
END

ELSE
BEGIN
PRINT 'emre'
END