support FILTER not only for window function (#1046)

* support FILTER not only for window function

* Fixed imports

Author: tvar

src/main/java/net/sf/jsqlparser/expression/AnalyticExpression.java

@@ -195,10 +195,15 @@ public String toString() {
         if (filterExpression != null) {
             b.append("FILTER (WHERE ");
             b.append(filterExpression.toString());
-            b.append(") ");
+            b.append(")");
+            if (type != AnalyticType.FILTER_ONLY) {
+                b.append(" ");
+            }
         }
 
         switch (type) {
+            case FILTER_ONLY:
+                return b.toString();
             case WITHIN_GROUP:
                 b.append("WITHIN GROUP");
                 break;

src/main/java/net/sf/jsqlparser/expression/AnalyticType.java

@@ -11,5 +11,6 @@
 
 public enum AnalyticType {
     OVER,
-    WITHIN_GROUP
+    WITHIN_GROUP,
+    FILTER_ONLY
 }

src/main/java/net/sf/jsqlparser/util/deparser/ExpressionDeParser.java

@@ -14,6 +14,7 @@
 
 import net.sf.jsqlparser.expression.AllComparisonExpression;
 import net.sf.jsqlparser.expression.AnalyticExpression;
+import net.sf.jsqlparser.expression.AnalyticType;
 import net.sf.jsqlparser.expression.AnyComparisonExpression;
 import net.sf.jsqlparser.expression.ArrayExpression;
 import net.sf.jsqlparser.expression.BinaryExpression;
@@ -706,10 +707,15 @@ public void visit(AnalyticExpression aexpr) {
         if (aexpr.getFilterExpression() != null) {
             buffer.append("FILTER (WHERE ");
             aexpr.getFilterExpression().accept(this);
-            buffer.append(") ");
+            buffer.append(")");
+            if (aexpr.getType() != AnalyticType.FILTER_ONLY) {
+                buffer.append(" ");
+            }
         }
 
         switch (aexpr.getType()) {
+            case FILTER_ONLY:
+                return;
             case WITHIN_GROUP:
                 buffer.append("WITHIN GROUP");
                 break;

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -3434,25 +3434,13 @@ KeepExpression KeepExpression() : {
     }
 }
 
-AnalyticExpression AnalyticExpression(Function function) :
-{
-    AnalyticExpression retval = new AnalyticExpression(function);
-    ExpressionList expressionList = null;
-    List<OrderByElement> olist = null;
-    Token token = null;
-    Expression expr = null;
-    Expression offset = null;
-    Expression defaultValue = null;
-    WindowElement windowElement = null;
-    //KeepExpression keep = null;
-    //boolean distinct = false;
-    boolean partitionByBrackets = false;
-    Expression filter = null;
-}
-{
-
-    [ <K_FILTER> "(" <K_WHERE> filter = Expression() ")" ]
 
+void windowFun(AnalyticExpression retval):{
+         ExpressionList expressionList = null;
+         List<OrderByElement> olist = null;
+         WindowElement windowElement = null;
+         boolean partitionByBrackets = false;
+} {
     (<K_OVER> {retval.setType(AnalyticType.OVER);}
         | <K_WITHIN> <K_GROUP> {retval.setType(AnalyticType.WITHIN_GROUP);} )
 
@@ -3463,15 +3451,24 @@ AnalyticExpression AnalyticExpression(Function function) :
         ]
         [olist=OrderByElements() ]
         [windowElement = WindowElement() ]
+        {
+            retval.setPartitionExpressionList(expressionList, partitionByBrackets);
+            retval.setOrderByElements(olist);
+            retval.setWindowElement(windowElement);
+        }
+    ")"
+}
 
+AnalyticExpression AnalyticExpression(Function function) :
+{
+    AnalyticExpression retval = new AnalyticExpression(function);
+    Expression filter = null;
+}
+{
+    ((<K_FILTER> "(" <K_WHERE> {retval.setType(AnalyticType.FILTER_ONLY);} filter = Expression() ")" [ LOOKAHEAD(2) windowFun(retval) ] )
+        | windowFun(retval))
     {
-        retval.setPartitionExpressionList(expressionList, partitionByBrackets);
-        retval.setOrderByElements(olist);
-        retval.setWindowElement(windowElement);
         retval.setFilterExpression(filter);
-    }
-    ")"
-    {
         return retval;
     }
 }

src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java

@@ -1978,6 +1978,11 @@ public void testAnalyticPartitionBooleanExpressionIssue864_2() throws JSQLParser
         assertSqlCanBeParsedAndDeparsed("SELECT COUNT(*) OVER (PARTITION BY (event = 'admit' OR event = 'family visit') ) family_visits FROM patients");
     }
 
+    @Test
+    public void testAnalyticFunctionFilterIssue934() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT COUNT(*) FILTER (WHERE name = 'Raj') FROM table");
+    }
+
     @Test
     public void testFunctionLeft() throws JSQLParserException {
         String statement = "SELECT left(table1.col1, 4) FROM table1";