java - finding max(column) where column is varchar type using hibernate query -

hi have column of type varchar example:

1 2 3 4 5 

i wanted max value tried following query

select max(sianswersid) < table> 

but gives me wrong output tried using

max(cast(sianswersid integer)) , works fine when run in sql developer

but when frame query in hibernate as

select max(cast(si_answers_id integer)) < table>  

it gives me below error

no data type node: org.hibernate.hql.internal.ast.tree.aggregatenode  <| \-[aggregate] aggregatenode: 'max'<|    \-[method_call] methodnode: '('<|        +-[method_name] identnode: 'cast' {originaltext=cast}<|        \-[expr_list] sqlnode: 'exprlist'<|           +-[dot] dotnode: 'serviceins0_.si_answers_id' {propertyname=sianswersid,dereferencetype=primitive,getpropertypath=sianswersid,path {synthetic-alias}.sianswersid,tablealias=serviceins0_, classname=com.hp.api.management.nfv.questionnair.entities.serviceinstanceanswersentity, classalias=s}<|       |  +-[ident] identnode: '{synthetic-alias}' {originaltext={synthetic-alias}}<|       |  \-[ident] identnode: 'sianswersid' {originaltext=sianswersid}<|       \-[ident] identnode: 'int' {originaltext=int}<| 

actually "int" must lowercase as

max(cast(sianswersid int))  

it doesn't work int, integer, or integer. message says "no data type" doesn't recognize these valid data type.