Add support for IS DISTINCT FROM clause (#1457)

Co-authored-by: Tomer Shay <[email protected]>

Author: tomershay

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

@@ -186,4 +186,6 @@ public interface ExpressionVisitor {
     void visit(AllTableColumns allTableColumns);
 
     void visit(AllValue allValue);
+
+    void visit(IsDistinctExpression isDistinctExpression);
 }

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

@@ -504,6 +504,11 @@ public void visit(AllTableColumns allTableColumns) {
     public void visit(AllValue allValue) {
     }
 
+    @Override
+    public void visit(IsDistinctExpression isDistinctExpression) {
+        visitBinaryExpression(isDistinctExpression);
+    }
+
     @Override
     public void visit(SelectExpressionItem selectExpressionItem) {
         selectExpressionItem.getExpression().accept(this);

src/main/java/net/sf/jsqlparser/expression/operators/relational/IsDistinctExpression.java

@@ -0,0 +1,42 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2019 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.expression.operators.relational;
+
+import net.sf.jsqlparser.expression.BinaryExpression;
+import net.sf.jsqlparser.expression.ExpressionVisitor;
+
+public class IsDistinctExpression extends BinaryExpression {
+
+    private boolean not = false;
+
+    public boolean isNot() {
+        return not;
+    }
+
+    public void setNot(boolean b) {
+        not = b;
+    }
+
+    @Override
+    public void accept(ExpressionVisitor expressionVisitor) {
+        expressionVisitor.visit(this);
+    }
+
+    @Override
+    public String getStringExpression() {
+        return " IS " + (isNot() ? "NOT " : "") + "DISTINCT FROM ";
+    }
+
+    @Override
+    public String toString() {
+        String retval = getLeftExpression() + getStringExpression() + getRightExpression();
+        return retval;
+    }
+}

src/main/java/net/sf/jsqlparser/util/TablesNamesFinder.java

@@ -576,6 +576,11 @@ public void visit(AllValue allValue) {
 
     }
 
+    @Override
+    public void visit(IsDistinctExpression isDistinctExpression) {
+        visitBinaryExpression(isDistinctExpression);
+    }
+
     @Override
     public void visit(SelectExpressionItem item) {
         item.getExpression().accept(this);

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

@@ -52,6 +52,7 @@
 import net.sf.jsqlparser.expression.operators.relational.RegExpMatchOperator;
 import net.sf.jsqlparser.expression.operators.relational.RegExpMySQLOperator;
 import net.sf.jsqlparser.expression.operators.relational.SimilarToExpression;
+import net.sf.jsqlparser.expression.operators.relational.IsDistinctExpression;
 import net.sf.jsqlparser.expression.operators.relational.SupportsOldOracleJoinSyntax;
 import net.sf.jsqlparser.schema.Column;
 import net.sf.jsqlparser.schema.Table;
@@ -988,4 +989,11 @@ public void visit(AllTableColumns allTableColumns) {
     public void visit(AllValue allValue) {
         buffer.append(allValue);
     }
+
+    @Override
+    public void visit(IsDistinctExpression isDistinctExpression) {
+        buffer.append(isDistinctExpression.getLeftExpression() +
+                isDistinctExpression.getStringExpression() +
+                isDistinctExpression.getRightExpression());
+    }
 }

src/main/java/net/sf/jsqlparser/util/validation/validator/ExpressionValidator.java

@@ -45,6 +45,7 @@
 import net.sf.jsqlparser.expression.operators.relational.RegExpMatchOperator;
 import net.sf.jsqlparser.expression.operators.relational.RegExpMySQLOperator;
 import net.sf.jsqlparser.expression.operators.relational.SimilarToExpression;
+import net.sf.jsqlparser.expression.operators.relational.IsDistinctExpression;
 import net.sf.jsqlparser.expression.operators.relational.SupportsOldOracleJoinSyntax;
 import net.sf.jsqlparser.parser.feature.Feature;
 import net.sf.jsqlparser.schema.Column;
@@ -579,4 +580,10 @@ public void visit(AllValue allValue) {
 
     }
 
+    @Override
+    public void visit(IsDistinctExpression isDistinctExpression) {
+        isDistinctExpression.getLeftExpression().accept(this);
+        isDistinctExpression.getRightExpression().accept(this);
+    }
+
 }

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

@@ -3149,6 +3149,7 @@ Expression SQLCondition():
          | LOOKAHEAD(IsNullExpression()) result=IsNullExpression(left)
          | LOOKAHEAD(IsBooleanExpression()) result=IsBooleanExpression(left)
          | LOOKAHEAD(2) result=LikeExpression(left)
+         | LOOKAHEAD(IsDistinctExpression()) result=IsDistinctExpression(left)
          | result=SimilarToExpression(left)
         )) ]
     )
@@ -3266,6 +3267,22 @@ Expression SimilarToExpression(Expression leftExpression) #SimilarToExpression:
     }
 }
 
+Expression IsDistinctExpression(Expression leftExpression) #IsDistinctExpression:
+{
+    IsDistinctExpression result = new IsDistinctExpression();
+    Expression rightExpression = null;
+}
+{
+    <K_IS> [<K_NOT> { result.setNot(true); } ] <K_DISTINCT> <K_FROM>
+    rightExpression=SimpleExpression()
+    {
+        result.setLeftExpression(leftExpression);
+        result.setRightExpression(rightExpression);
+        linkAST(result,jjtThis);
+        return result;
+    }
+}
+
 Expression IsNullExpression(Expression leftExpression):
 {
     IsNullExpression result = new IsNullExpression();

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

@@ -961,6 +961,18 @@ public void testDistinct() throws JSQLParserException {
         assertStatementCanBeDeparsedAs(select, statement);
     }
 
+    @Test
+    public void testIsDistinctFrom() throws JSQLParserException {
+        String stmt = "SELECT name FROM tbl WHERE name IS DISTINCT FROM foo";
+        assertSqlCanBeParsedAndDeparsed(stmt);
+    }
+
+    @Test
+    public void testIsNotDistinctFrom() throws JSQLParserException {
+        String stmt = "SELECT name FROM tbl WHERE name IS NOT DISTINCT FROM foo";
+        assertSqlCanBeParsedAndDeparsed(stmt);
+    }
+
     @Test
     public void testDistinctTop() throws JSQLParserException {
         String statement = "SELECT DISTINCT TOP 5 myid, mycol FROM mytable WHERE mytable.col = 9";