character comparison in oracle sql

I have the following query in sql

<span class="kwd" style="color: #00008b;">SELECT</span><span class="pln" style="color: #000000;"> SUM</span><span class="pun" style="color: #000000;">(</span><span class="pln" style="color: #000000;">WT</span><span class="pun" style="color: #000000;">.</span><span class="pln" style="color: #000000;">TRANSACTION_QUANTITY </span><span class="pun" style="color: #000000;">*</span><span class="pln" style="color: #000000;"> WTA</span><span class="pun" style="color: #000000;">.</span><span class="pln" style="color: #000000;">RATE_OR_AMOUNT</span><span class="pun" style="color: #000000;">)</span><span class="pln" style="color: #000000;"> </span><span class="kwd" style="color: #00008b;">FROM</span><span class="pln" style="color: #000000;"> WIP_TRANSACTION_ACCOUNTS WTA</span><span class="pun" style="color: #000000;">,</span><span class="pln" style="color: #000000;"> WIP_TRANSACTIONS WT </span><span class="kwd" style="color: #00008b;">WHERE</span><span class="pln" style="color: #000000;"> WTA</span><span class="pun" style="color: #000000;">.</span><span class="pln" style="color: #000000;">TRANSACTION_ID </span><span class="pun" style="color: #000000;">=</span><span class="pln" style="color: #000000;"> WT</span><span class="pun" style="color: #000000;">.</span><span class="pln" style="color: #000000;">TRANSACTION_ID </span><span class="kwd" style="color: #00008b;">AND</span><span class="pln" style="color: #000000;"> WTA</span><span class="pun" style="color: #000000;">.</span><span class="pln" style="color: #000000;">ORGANIZATION_ID </span><span