Fixed bug when using null

Author: CollinAlpert

README.MD

@@ -56,7 +56,7 @@ You can include the Maven dependency:
 <dependency>
     <groupId>com.github.collinalpert</groupId>
     <artifactId>lambda2sql</artifactId>
-    <version>1.8.2</version>
+    <version>1.8.3</version>
 </dependency>
 ```
 

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.github.collinalpert</groupId>
     <artifactId>lambda2sql</artifactId>
-    <version>1.8.2</version>
+    <version>1.8.3</version>
     <packaging>jar</packaging>
 
     <name>lambda2sql</name>

src/main/java/com/github/collinalpert/lambda2sql/ToSqlVisitor.java

@@ -66,13 +66,7 @@ public StringBuilder visit(BinaryExpression e) {
 		if (quote) sb.append('(');
 
 		e.getFirst().accept(this);
-		sb.append(' ');
-		if (!arguments.isEmpty() && arguments.top().get(0).getValue() == null) {
-			sb.append("IS");
-		} else {
-			sb.append(toSqlOp(e.getExpressionType()));
-		}
-		sb.append(' ');
+		sb.append(' ').append(toSqlOp(e.getExpressionType())).append(' ');
 		e.getSecond().accept(this);
 
 		if (quote) sb.append(')');
@@ -90,7 +84,9 @@ public StringBuilder visit(BinaryExpression e) {
 	@Override
 	public StringBuilder visit(ConstantExpression e) {
 		if (e.getValue() == null) {
-			return sb.append("NULL");
+			sb.deleteCharAt(sb.length() - 1);
+			sb.delete(sb.lastIndexOf(" "), sb.length());
+			return sb.append(" IS NULL");
 		}
 		if (e.getValue() instanceof String) {
 			return sb.append("'").append(e.getValue().toString()).append("'");

src/test/java/com/github/collinalpert/lambda2sql/test/Lambda2SqlTest.java

@@ -87,10 +87,13 @@ void testNestedProperties() {
 	@Test
 	void testNull() {
 		String isNull = null;
+		Integer i = null;
 		SqlPredicate<IPerson> p = person -> person.getName() == isNull;
 		SqlPredicate<IPerson> p2 = person -> person.getName() == null;
+		SqlPredicate<IPerson> p3 = person -> person.getAge() >= i;
 		assertPredicateEqual("person.name IS NULL", p);
 		assertPredicateEqual("person.name IS NULL", p2);
+		assertPredicateEqual("person.age IS NULL", p3);
 	}
 
 	private void assertPredicateEqual(String expectedSql, SqlPredicate<IPerson> p) {