Merge lp:~mmcm/akiban-server/simple-case into lp:~akiban-technologies/akiban-server/trunk

[Mike McMahon]

Handle simple CASE added by lp:~mmcm/akiban-sql-parser/simple-case.

Note that this just turns it into the corresponding search case: it does each comparison as a separate expression.

It would be reasonable to have an expression that took a single value and matched it against a list of clauses, possibly with special handling for the common case of constants, which it could hash or binary search. But, in my opinion, the right way to introduce that is from suitable nested IfElseExpression's _after_ constant folding. That way either syntax gets the desired improvements. I didn't do any of this because it might interfere with ripping types2 out, which is enough of a big deal already.

[Thomas Jones-Low (tjoneslo)]

As described

review: Approve

[Thomas Jones-Low (tjoneslo)]

There were 2 failures during build/test:

* job server-build failed at build number 4162: http://sneezy.softstart.com:8080/job/server-build/4162/

* view must-pass failed: server-build is red

review: Needs Fixing

[Mike McMahon (mmcm)]

Needed to wait for parser.

review: Approve

=== modified file 'pom.xml'
--- pom.xml	2013-07-30 18:46:57 +0000
+++ pom.xml	2013-07-31 20:57:25 +0000
@@ -100,7 +100,7 @@
         <dependency>
             <groupId>com.akiban</groupId>
             <artifactId>akiban-sql-parser</artifactId>
-            <version>1.0.15-SNAPSHOT</version>
+            <version>1.0.16-SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
 
=== modified file 'src/main/java/com/akiban/sql/optimizer/rule/ASTStatementLoader.java'
--- src/main/java/com/akiban/sql/optimizer/rule/ASTStatementLoader.java	2013-03-22 20:05:57 +0000
+++ src/main/java/com/akiban/sql/optimizer/rule/ASTStatementLoader.java	2013-07-31 20:57:25 +0000
@@ -1545,6 +1545,24 @@
                                             toExpression(cond.getElseNode(), projects),
                                             cond.getType(), cond);
             }
+            else if (valueNode instanceof SimpleCaseNode) {
+                SimpleCaseNode caseNode = (SimpleCaseNode)valueNode;
+                ExpressionNode operand = toExpression(caseNode.getOperand(), projects);
+                int ncases = caseNode.getNumberOfCases();
+                ExpressionNode expr;
+                if (caseNode.getElseValue() != null)
+                    expr = toExpression(caseNode.getElseValue(), projects);
+                else
+                    expr = new ConstantExpression(null, AkType.NULL);
+                for (int i = ncases - 1; i >= 0; i--) {
+                    ConditionList conds = new ConditionList(1);
+                    conds.add(new ComparisonCondition(Comparison.EQ, operand, toExpression(caseNode.getCaseOperand(i), projects), caseNode.getType(), caseNode));
+                    expr = new IfElseExpression(conds,
+                                                toExpression(caseNode.getResultValue(i), projects),
+                                                expr, caseNode.getType(), caseNode);
+                }
+                return expr;
+            }
             else if (valueNode instanceof NextSequenceNode) {
                 NextSequenceNode seqNode = (NextSequenceNode)valueNode;
                 List<ExpressionNode> params = new ArrayList<>(2);
 
=== modified file 'src/test/resources/com/akiban/sql/optimizer/rule/parse/README.txt'
--- src/test/resources/com/akiban/sql/optimizer/rule/parse/README.txt	2012-09-18 22:33:15 +0000
+++ src/test/resources/com/akiban/sql/optimizer/rule/parse/README.txt	2013-07-31 20:57:25 +0000
@@ -18,7 +18,9 @@
 
 between-3: NOT BETWEEN condition
 
-case-1: CASE statement
+case-1: search CASE statement
+
+case-2: simple CASE statement
 
 cast-1: explicit CAST
 
 
=== added file 'src/test/resources/com/akiban/sql/optimizer/rule/parse/case-2.expected'
--- src/test/resources/com/akiban/sql/optimizer/rule/parse/case-2.expected	1970-01-01 00:00:00 +0000
+++ src/test/resources/com/akiban/sql/optimizer/rule/parse/case-2.expected	2013-07-31 20:57:25 +0000
@@ -0,0 +1,5 @@
+SelectQuery@1290b1e8
+  ResultSet@598fffdd[_SQL_COL_1]
+    Project@7ce7341a[IF([items.sku == 1234], apples, IF([items.sku == 9876], oranges, unknown))]
+      Select@116db99a[]
+        TableSource@3ab43666(items)
 \ No newline at end of file
 
=== added file 'src/test/resources/com/akiban/sql/optimizer/rule/parse/case-2.sql'
--- src/test/resources/com/akiban/sql/optimizer/rule/parse/case-2.sql	1970-01-01 00:00:00 +0000
+++ src/test/resources/com/akiban/sql/optimizer/rule/parse/case-2.sql	2013-07-31 20:57:25 +0000
@@ -0,0 +1,5 @@
+SELECT CASE sku
+       WHEN '1234' THEN 'apples'
+       WHEN '9876' THEN 'oranges'
+       ELSE 'unknown' END
+  FROM items