SQL query help pls

i have the follwoing data 

patno hospno Roomcode

1   123

1   124

i have another table 

patno hospno  proc_code 

1     123      256

1     123       258

1     123       300

1  124      500

i have  another table chargemaster

proc_code department 

258         701

200         701

could you pls tell me how to write a query to accomplish the follwing

i have to get all proc codes for department 701

now, i have to see if the patno and unitnum in the very first table have a proc code that belongs to department 701, if yes, i have to mark that record with 1

in this scenario, since 1 123 has one of the proc codes to be 258 which belongs to deartment 701, it gets marked with 1

please help.

thanks a lot

nik