How to Concatenate %?

Question

I have a requirement where I need to concatenate '%' with the column value in the where clause dynamically.
For Example
Select Attr1,attr2....attr10
From tab1 a,tab2 b
Where a.attr3 like '||b.attr3||'
suppose if the value for b.attr3 is 'test' then I need it this way
where a.attr3 like 'test%'
I tried with '||b.attr3||'%'||' and other methods ...but not able to achieve the result.
Can anyone help?

Answer 1

Select Attr1,attr2....attr10
  From tab1 a,tab2 b
Where a.attr3 like ''''||b.attr3||'%'||'''';note: untested.
or you can do a
Select Attr1,attr2....attr10
  From tab1 a,tab2 b
Where substr(a.attr3,1,length(b.attr3)) = b.attr3;
SQL> select ename from emp
  2   where substr(ename,1,length('&pName')) = '&pName';
Enter value for pname: A
Enter value for pname: A
old   2:  where substr(ename,1,length('&pName')) = '&pName'
new   2:  where substr(ename,1,length('A')) = 'A'
ENAME
ALLEN
ADAMS
SQL>