I will answer on my own problem Maybe someone will find it useful.
I did a part of script like this:
repeat('_',(STDT-20120101)*24+round(MSTI/100)-1) & Repeat('X',(FIDT-20120101)*24+round(MFTI/100)-(STDT-20120101)*24+round(MSTI/100)) as GANT_CHART
STDT = start date,
MSTI = start time,
FIDT = finish date,
MFTI = finish time,
I treated date 20120101 as a beginning of the period I'd like to see.
So as a result my table could look like this:
Order GANT_CHART MO_1 _________XXXXXXX MO_2 _______________XXXXXXXXXXXXXXXXX MO_3 _____________________XXXXXXXX
Quite nice as for a short piece of code