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--- sql-derivative-sensitivity-analyser_demo [2019/06/01 15:43]
alisa [Setting up data objects]
+++ sql-derivative-sensitivity-analyser_demo [2019/06/01 15:46]
alisa [Setting up tasks]
@@ Line 66: / Line 66: @@
 ==== Setting up tasks ====
-Click on the task ''Estimate the first arrival''. We need to insert here a query. Let the query return the earliest time when some ship arrives at the port located at the point (0,0). We assume that each ship starts moving at its maximum speed.
+Click on the task ''Estimate the first arrival''. We need to insert here a query, and a schema of the table that results from executing that query. Let the query return the earliest time when some ship arrives at the port located at the point (0,0). We assume that each ship starts moving at its maximum speed.
+The output table schema defines a table that contains just a single column.
 <code>
-create or replace function min_time() returns TABLE (
+create table min_time(cnt INT8);
-  cnt INT8
+</code>
-) as $$
+The output table query describes how the arrival time is computed from ship location and its speed.
+<code>
 SELECT
-    MIN ((ship.latitude ^ 2 + ship.longitude ^ 2) ^ 0.5 / ship.max_speed)
+    MIN ((ship.latitude ^ 2 + ship.longitude ^ 2) ^ 0.5 / ship.max_speed) AS cnt
 FROM
     ship
-$$ language SQL;
+;
 </code>

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