Merge pull request #1661 from katzyn/ratio_to_report

Add RATIO_TO_REPORT window function

h2/src/docsrc/help/help.csv

@@ -5547,6 +5547,19 @@ SELECT NTH_VALUE(X) IGNORE NULLS OVER (
 ), * FROM TEST;
 "
 
+"Functions (Window)","RATIO_TO_REPORT","
+RATIO_TO_REPORT(value)
+OVER windowNameOrSpecification
+","
+Returns the ratio of a value to the sum of all values.
+If argument is NULL or sum of all values is 0, then the value of function is NULL.
+
+Window functions are currently experimental in H2 and should be used with caution.
+They also may require a lot of memory for large queries.
+","
+SELECT X, RATIO_TO_REPORT(X) OVER (PARTITION BY CATEGORY), CATEGORY FROM TEST;
+"
+
 "System Tables","Information Schema","
 INFORMATION_SCHEMA
 ","

h2/src/main/org/h2/expression/analysis/WindowFunction.java

@@ -48,6 +48,7 @@ public class WindowFunction extends DataAnalysisOperation {
         case LAG:
         case FIRST_VALUE:
         case LAST_VALUE:
+        case RATIO_TO_REPORT:
             return 1;
         case NTH_VALUE:
             return 2;
@@ -68,6 +69,7 @@ public class WindowFunction extends DataAnalysisOperation {
         case NTILE:
         case FIRST_VALUE:
         case LAST_VALUE:
+        case RATIO_TO_REPORT:
             return 1;
         case LEAD:
         case LAG:
@@ -207,6 +209,9 @@ public class WindowFunction extends DataAnalysisOperation {
         case NTH_VALUE:
             getNth(session, result, ordered, rowIdColumn);
             break;
+        case RATIO_TO_REPORT:
+            getRatioToReport(session, result, ordered, rowIdColumn);
+            break;
         default:
             throw DbException.throwInternalError("type=" + type);
         }
@@ -375,6 +380,38 @@ public class WindowFunction extends DataAnalysisOperation {
         }
     }
 
+    private static void getRatioToReport(Session session, HashMap<Integer, Value> result, ArrayList<Value[]> ordered,
+            int rowIdColumn) {
+        int size = ordered.size();
+        Value value = null;
+        for (int i = 0; i < size; i++) {
+            Value v = ordered.get(i)[0];
+            if (v != ValueNull.INSTANCE) {
+                if (value == null) {
+                    value = v.convertTo(Value.DOUBLE);
+                } else {
+                    value = value.add(v.convertTo(Value.DOUBLE));
+                }
+            }
+        }
+        if (value != null && value.getSignum() == 0) {
+            value = null;
+        }
+        for (int i = 0; i < size; i++) {
+            Value[] row = ordered.get(i);
+            Value v;
+            if (value == null) {
+                v = ValueNull.INSTANCE;
+            } else {
+                v = row[0];
+                if (v != ValueNull.INSTANCE) {
+                    v = v.convertTo(Value.DOUBLE).divide(value);
+                }
+            }
+            result.put(row[rowIdColumn].getInt(), v);
+        }
+    }
+
     @Override
     protected Value getAggregatedValue(Session session, Object aggregateData) {
         throw DbException.getUnsupportedException("Window function");
@@ -444,6 +481,7 @@ public class WindowFunction extends DataAnalysisOperation {
             return Value.LONG;
         case PERCENT_RANK:
         case CUME_DIST:
+        case RATIO_TO_REPORT:
             return Value.DOUBLE;
         case LEAD:
         case LAG:
@@ -480,6 +518,7 @@ public class WindowFunction extends DataAnalysisOperation {
             return ValueLong.PRECISION;
         case PERCENT_RANK:
         case CUME_DIST:
+        case RATIO_TO_REPORT:
             return ValueDouble.PRECISION;
         case LEAD:
         case LAG:
@@ -502,6 +541,7 @@ public class WindowFunction extends DataAnalysisOperation {
             return ValueLong.DISPLAY_SIZE;
         case PERCENT_RANK:
         case CUME_DIST:
+        case RATIO_TO_REPORT:
             return ValueDouble.DISPLAY_SIZE;
         case LEAD:
         case LAG:

h2/src/main/org/h2/expression/analysis/WindowFunctionType.java

@@ -65,6 +65,11 @@ public enum WindowFunctionType {
      */
     NTH_VALUE,
 
+    /**
+     * The type for RATIO_TO_REPORT() window function.
+     */
+    RATIO_TO_REPORT,
+
     ;
 
     /**
@@ -98,6 +103,8 @@ public enum WindowFunctionType {
             return LAST_VALUE;
         case "NTH_VALUE":
             return NTH_VALUE;
+        case "RATIO_TO_REPORT":
+            return RATIO_TO_REPORT;
         default:
             return null;
         }

h2/src/test/org/h2/test/scripts/TestScript.java

@@ -204,7 +204,7 @@ public class TestScript extends TestDb {
                 "parsedatetime", "quarter", "second", "truncate", "week", "year", "date_trunc" }) {
             testScript("functions/timeanddate/" + s + ".sql");
         }
-        for (String s : new String[] { "lead", "nth_value", "ntile", "row_number" }) {
+        for (String s : new String[] { "lead", "nth_value", "ntile", "ratio_to_report", "row_number" }) {
             testScript("functions/window/" + s + ".sql");
         }
 

h2/src/test/org/h2/test/scripts/functions/window/ratio_to_report.sql

+-- Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
+-- and the EPL 1.0 (http://h2database.com/html/license.html).
+-- Initial Developer: H2 Group
+--
+
+CREATE TABLE TEST(ID INT PRIMARY KEY, N NUMERIC);
+> ok
+
+INSERT INTO TEST VALUES(1, 1), (2, 2), (3, NULL), (4, 5);
+> update count: 4
+
+SELECT ID, N, RATIO_TO_REPORT(N) OVER() R2R FROM TEST;
+> ID N    R2R
+> -- ---- -----
+> 1  1    0.125
+> 2  2    0.25
+> 3  null null
+> 4  5    0.625
+> rows: 4
+
+INSERT INTO TEST VALUES (5, -8);
+> update count: 1
+
+SELECT ID, N, RATIO_TO_REPORT(N) OVER() R2R FROM TEST;
+> ID N    R2R
+> -- ---- ----
+> 1  1    null
+> 2  2    null
+> 3  null null
+> 4  5    null
+> 5  -8   null
+> rows: 5
+
+DROP TABLE TEST;
+> ok