if you have created the block as database block of table type then you can write the search condition in Where clause of Database block by using the concatenation of all fields in folloiwing manner
--write in where clause of datablock
upper(column1||column2||column3) like '%'||:search_field||'%'
in runtime it will execute in following manner...
SELECT column1, column2 ,column3 from table
where upper(column1||column2||column3) like '%'||:search_field||'%'
then EXECUTE QUERY ON BLOCK will filter the records on the base of you query results.
Hope this will help you out..
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