condition with dates

Hi All,

I created a condition based on dates and inserted in the details section of the design.

Instead checking the condition and giving the right output, itis showing all the records.

Is my condition getting checked or not...it is displaying the all other records except the conditional ones.

i am cheking the dates with the prompt parameters. is this the right way to do or not?

if ({?z_stdt} >= {MG_M09_MG_M09_Q105.D_[MGSDT]K} and {?z_enddt} >= {MG_M09_MG_M09_Q105.D_[MGEDT]K})

then GroupName ({MG_M09_MG_M09_Q105.D_{[MG_CH60]}K}) else " "

this is the above logic...could some one pls help?