When we use the " & " function in TDV , the result seen via TDV Studio shows an INT8AND being used instead. As SQL Server data source, on which INT8AND is not supported, the function will not push to the DB engine. 

To resolve the issue, we need to make changes in capabilities file of SQL data source.

follow below steps to push & function in TDV ( for SQL data source ) :

1) Go to install directory>>conf>>adapters>>microsoft_sql_server_2012

2) Open file microsoft_sql_server_2012_values.xml

3) Add these lines within the root element <common:attributes>.
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<common:attribute xmlns:common="http://www.compositesw.com/services/system/util/common">
  <common:name>/custom/INT8AND(~any,~any)</common:name>
  <common:type>STRING</common:type>
  <common:value>($1 &amp; $2)</common:value>
  <common:configID>INT8AND(~any,~any)</common:configID>
</common:attribute>
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4) Restart the services for TDV server.