Ignory all value if marked "Select-All" in reports

Hello! < xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

I have SQL query in my report, using multi-value parameters:

Select Table1.Item

From Table1

Where Table1.Item in(@item)

Multi-value parameters “item”  have properties  “Available values” From-query and returned ~200 values. I want, If   I selected in my reports “Select-All” then  SQL query ignore “Where Table1.Item in(@item)”  How

Sorry my bad English :-)

Thanks!