java jdbc xml sql condtional with in cdata

Hi I am very new to Java and have inherited a spring pattern. I want to know if there is a way to do a conditional in the xml.

Here is the scenario

<value>
  <![CDATA[
      SELECT * FROM table WHERE a=:a
  ]]
</value> 

Here is what I want to do base on a global flag

<value>
  <![CDATA[
      SELECT * FROM table WHERE a=:a
   <if global >
      AND b=:b
   </if>
  ]]
</value> 

I am not sure about the syntax or it this is even possible inside of CDATA

Thanks in advance for any help.