diff --git a/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/StatementAnalyzer.java b/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/StatementAnalyzer.java
index 6a794763e1eec..caa4acb5e6baa 100644
--- a/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/StatementAnalyzer.java
+++ b/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/StatementAnalyzer.java
@@ -46,6 +46,7 @@
 import com.facebook.presto.spi.PrestoWarning;
 import com.facebook.presto.spi.SchemaTableName;
 import com.facebook.presto.spi.StandardErrorCode;
+import com.facebook.presto.spi.StandardWarningCode;
 import com.facebook.presto.spi.TableHandle;
 import com.facebook.presto.spi.WarningCollector;
 import com.facebook.presto.spi.analyzer.AccessControlInfoForTable;
@@ -763,6 +764,9 @@ protected Scope visitCreateTableAsSelect(CreateTableAsSelect node, Optional<Scop
             if (metadataResolver.tableExists(targetTable)) {
                 if (node.isNotExists()) {
                     analysis.setCreateTableAsSelectNoOp(true);
+                    warningCollector.add(new PrestoWarning(
+                            StandardWarningCode.SEMANTIC_WARNING,
+                            format("Table '%s' already exists, skipping table creation", targetTable)));
                     return createAndAssignScope(node, scope, Field.newUnqualified(node.getLocation(), "rows", BIGINT));
                 }
                 throw new SemanticException(TABLE_ALREADY_EXISTS, node, "Destination table '%s' already exists", targetTable);
diff --git a/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/UtilizedColumnsAnalyzer.java b/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/UtilizedColumnsAnalyzer.java
index fc8752c3cef98..1bd9308bffb4d 100644
--- a/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/UtilizedColumnsAnalyzer.java
+++ b/presto-main-base/src/main/java/com/facebook/presto/sql/analyzer/UtilizedColumnsAnalyzer.java
@@ -247,16 +247,19 @@ protected Void visitQuerySpecification(QuerySpecification querySpec, Context con
 
             // Wildcards are unresolved in the QuerySpecification's list of SelectItem, so we use output expressions from analysis instead
             List<Expression> selectItems = analysis.getOutputExpressions(querySpec);
-            if (!context.prunable) {
-                // Examine all the output expressions
-                for (Expression expression : selectItems) {
-                    process(expression, context);
+            // selectItems can be null for statements like CREATE TABLE IF NOT EXISTS when the table already exists
+            if (selectItems != null) {
+                if (!context.prunable) {
+                    // Examine all the output expressions
+                    for (Expression expression : selectItems) {
+                        process(expression, context);
+                    }
                 }
-            }
-            else {
-                // Prune (Only examine output expressions that have been referenced)
-                for (FieldId fieldId : context.getFieldIdsToExploreInRelation(querySpec)) {
-                    process(selectItems.get(fieldId.getFieldIndex()), context);
+                else {
+                    // Prune (Only examine output expressions that have been referenced)
+                    for (FieldId fieldId : context.getFieldIdsToExploreInRelation(querySpec)) {
+                        process(selectItems.get(fieldId.getFieldIndex()), context);
+                    }
                 }
             }
 
diff --git a/presto-main-base/src/test/java/com/facebook/presto/sql/analyzer/TestAnalyzer.java b/presto-main-base/src/test/java/com/facebook/presto/sql/analyzer/TestAnalyzer.java
index c3236d3e6627a..eeef49e6805f5 100644
--- a/presto-main-base/src/test/java/com/facebook/presto/sql/analyzer/TestAnalyzer.java
+++ b/presto-main-base/src/test/java/com/facebook/presto/sql/analyzer/TestAnalyzer.java
@@ -125,6 +125,13 @@ private static void assertNoWarning(WarningCollector warningCollector)
         assertTrue(warnings.isEmpty());
     }
 
+    @Test
+    public void testCTASIfNotExistsWhenExists()
+    {
+        assertHasWarning(analyzeWithWarnings("CREATE TABLE IF NOT EXISTS t1 AS SELECT a, b FROM t1"),
+                SEMANTIC_WARNING, "Table 'tpch.s1.t1' already exists, skipping table creation");
+    }
+
     @Test
     public void testNonComparableGroupBy()
     {