feat: Databricks Aggregate functions

Signed-off-by: Andreas Reichel <andreas@manticore-projects.com>

src/main/java/ai/starlake/transpiler/JSQLExpressionTranspiler.java

@@ -84,7 +84,9 @@ public class JSQLExpressionTranspiler extends ExpressionDeParser {
       {"column", "reserved"}, {"constraint", "reserved"}, {"create", "reserved"},
       {"default", "reserved"}, {"deferrable", "reserved"}, {"desc", "reserved"},
       {"describe", "reserved"}, {"distinct", "reserved"}, {"do", "reserved"}, {"else", "reserved"},
-      {"end", "reserved"}, {"except", "reserved"}, {"false", "reserved"}, {"fetch", "reserved"},
+      {"end", "reserved"}, {"except", "reserved"}
+          //, {"false", "reserved"}
+      , {"fetch", "reserved"},
       {"for", "reserved"}, {"foreign", "reserved"}, {"from", "reserved"}, {"grant", "reserved"},
       {"group", "reserved"}, {"having", "reserved"}, {"in", "reserved"}, {"initially", "reserved"},
       {"intersect", "reserved"}, {"into", "reserved"}, {"lateral", "reserved"},
@@ -502,6 +504,12 @@ public void visit(Function function) {
       function.getMultipartName().remove(0);
     }
 
+    if (function.isIgnoreNullsOutside()) {
+      warning("RESPECT/IGNORE NULLS is not supported for non-window functions.");
+      function.setNullHandling(null);
+      function.setIgnoreNullsOutside(false);
+    }
+
     Expression rewrittenExpression = null;
     ExpressionList<?> parameters = function.getParameters();
     TranspiledFunction f = TranspiledFunction.from(functionName);

src/main/java/ai/starlake/transpiler/databricks/DatabricksExpressionTranspiler.java

@@ -52,6 +52,8 @@ enum TranspiledFunction {
 
     , FROM_UNIXTIME, TO_UNIX_TIMESTAMP, MAKE_TIMESTAMP, TIMESTAMP, TO_TIMESTAMP
 
+    , ANY, APPROX_PERCENTILE
+
     ;
     // @FORMATTER:ON
 
@@ -418,6 +420,16 @@ public void visit(Function function) {
             rewrittenExpression = new CastExpression(parameters.get(0), "TIMESTAMP");
           }
           break;
+        case ANY:
+          function.setName("Any_Value");
+          break;
+        case APPROX_PERCENTILE:
+          function.setName("Approx_Quantile");
+          if (paramCount==3) {
+            warning("PRECISION parameter not supported");
+            parameters.remove(2);
+          }
+          break;
       }
     }
     if (rewrittenExpression == null) {
@@ -446,7 +458,14 @@ public void visit(AnalyticExpression function) {
     }
 
     Expression rewrittenExpression = null;
-    // TranspiledFunction f = TranspiledFunction.from(functionName);
+    TranspiledFunction f = TranspiledFunction.from(functionName);
+    if (f != null) {
+      switch (f) {
+        case ANY:
+          function.setName("Any_Value");
+          break;
+      }
+    }
     if (rewrittenExpression == null) {
       super.visit(function);
     } else {

src/test/resources/ai/starlake/transpiler/databricks/aggregate_function.sql

@@ -0,0 +1,56 @@
+-- provided
+SELECT any(col) AS bool FROM VALUES (true), (false), (false) AS tab(col);
+
+-- expected
+SELECT any_value(col) AS bool FROM VALUES (true), (false), (false) AS tab(col);
+
+-- result
+"bool"
+"true"
+
+
+-- provided
+SELECT any_value(col) IGNORE NULLS FROM VALUES (NULL), (5), (20) AS tab(col);
+
+-- expected
+select any_value(col) FROM VALUES (NULL), (5), (20) AS tab(col);
+
+-- count
+1
+
+
+-- provided
+SELECT approx_count_distinct(col1) FILTER(WHERE col2 = 10) AS count
+    FROM VALUES (1, 10), (1, 10), (2, 10), (2, 10), (3, 10), (1, 12) AS tab(col1, col2);
+
+-- result
+"count"
+"3"
+
+
+
+-- provided
+SELECT approx_percentile(DISTINCT col, 0.5, 100)  AS percentile FROM VALUES (0), (6), (6), (7), (9), (10) AS tab(col);
+
+-- expected
+SELECT approx_quantile(DISTINCT col, 0.5) AS percentile FROM VALUES (0), (6), (6), (7), (9), (10) AS tab(col);
+
+-- result
+"percentile"
+"7"
+
+
+-- provided
+SELECT array_agg(DISTINCT col) AS arr FROM VALUES (1), (2), (NULL), (1) AS tab(col);
+
+-- result
+"arr"
+"[1, null, 2]"
+
+
+-- provided
+SELECT avg(col) AS avg FROM VALUES (1), (2), (NULL) AS tab(col);
+
+-- result
+"avg"
+"1.50"

src/test/resources/ai/starlake/transpiler/databricks/todo

@@ -6,4 +6,15 @@ SELECT strftime( DATE '2016-04-08', 'y') AS s;
 
 -- result
 "s"
-"2016"
+"2016"
+
+
+-- provided
+SELECT approx_percentile(col, array(0.5, 0.4, 0.1), 100) AS percentile FROM VALUES (0), (1), (2), (10) AS tab(col);
+
+-- expected
+SELECT approx_quantile(col, ARRAY_VALUE(0.5, 0.4, 0.1)) AS percentile FROM VALUES (0), (1), (2), (10) AS tab(col);
+
+-- result
+"percentile"
+"[2, 1, 0]"