Merge pull request #11 from equella/issue/10

#10:  Add how to name parameters in Postgres

Invoking 'lazy consensus'.  Please open another PR if needed.

tutorials/reporting/README.md

@@ -41,6 +41,7 @@ these tutorials.
 Postgres:
 1. [Querying with the native XML type](postgres/QueryingXMLType.md)
 1. [Querying repeated metadata](postgres/RepeatedMetadata.md)
+1. [Querying with named parameters](postgres/NamingParameters.md)
 
 SQLServer:
 1. [Querying with the native XML type](sqlserver/QueryingXMLType.md)

tutorials/reporting/postgres/NamingParameters.md

@@ -0,0 +1,15 @@
+## Naming Parameters
+
+There are times when using the question mark syntax for bringing in parameters is not the best choice - a parameter might need to be used in multiple places, the number of parameters could make for a confusing SQL query, etc.  After setting up the Report and Data Set parameters appropriately, use the following SQL example as a guide to 'name' the parameters directly in the query.
+
+```sql
+with vars as (
+  select
+  ?::date as startdate,
+  ?::date as enddate
+)
+select uuid, version, date_created from item
+where
+  date_created >= (select startdate from vars) and
+  date_created <= (select enddate from vars)
+```