Differences Between the SQL-based and Fetch-based Reports

Area	SQL-based Report
Data Provider	The <DataProvider> element value in the .rdl file is set to SQL. For example: <DataProvider>SQL</DataProvider>
Report query	The query specified for retrieving data is in the <CommandText> sub-element under the<Query> element in the report definition (.rdl file) is a SQL query. For example, the query for retrieving all account names for a SQL-based report will be: <CommandText>SELECT name FROM FilteredAccount;</CommandText>

Area	Fetch-based report
Data Provider	The <DataProvider> element value in the .rdl file is set to MSCRMFETCH. For example: <DataProvider>MSCRMFETCH</DataProvider>
Report query	The query specified for retrieving data is in the <CommandText> sub-element under the <Query>  element in the report definition (.rdl file) is a FetchXML query. For example, the query for retrieving  all account names for a Fetch-based report will be: <CommandText>&lt;fetch version="1.0" output-format="xml-platform" mapping="logical"&gt;     &lt;entity name="account"&gt;         &lt;attribute name="name" /&gt;     &lt;/entity&gt; &lt;/fetch&gt;</CommandText>