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Note the string {customerId}. This is an example of how to pass data from your form fields into your SQL statements. For example, if your form field named customerId contains the value 1234 than the select statement would return the record for customer 1234.

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Retrieving NULL or Blank Database columns

By default, the database connector will not return any xml value or json value for any database column that is blank or null. If you want the database connector to return a empty string or null for such columns then set the emitNullColumns attribute to true. The emitNullColumns attribute can be set in these configuration.xml elements from highest to lowest precedence : <dbconnector>, <queryset>, or <query>. The outer elements take precedence over the inner elements. 

Here are several configuration.xml examples.

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