bug fixed for statementExecutableSqlLogEnable

src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlOutputVisitor.java

@@ -15,6 +15,7 @@
  */
 package com.alibaba.druid.sql.dialect.mysql.visitor;
 
+import java.util.List;
 import java.util.Map;
 
 import com.alibaba.druid.sql.ast.SQLCommentHint;
@@ -342,7 +343,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
             printAndAccept(x.getArguments(), ", ");
             print(")");
         }
-        
+
         if (x.getCharSetName() != null) {
             print(" CHARACTER SET ");
             print(x.getCharSetName());
@@ -521,6 +522,17 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
     }
 
     public boolean visit(SQLVariantRefExpr x) {
+        {
+            List<Object> parameters = this.getParameters();
+            int index = x.getIndex();
+
+            if (parameters != null && index >= 0 && index < parameters.size()) {
+                Object param = parameters.get(index);
+                printParameter(param);
+                return false;
+            }
+        }
+
         if (x.isGlobal()) {
             print("@@global.");
         } else {

src/main/java/com/alibaba/druid/sql/visitor/SQLASTOutputVisitor.java

@@ -700,56 +700,59 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter {
         }
 
         Object param = parameters.get(index);
+        printParameter(param);
+        return false;
+    }
 
+    public void printParameter(Object param) {
         if (param == null) {
             print("NULL");
-            return false;
+            return;
         }
 
         if (param instanceof Number //
             || param instanceof Boolean) {
             print(param.toString());
-            return false;
+            return;
         }
         
         if (param instanceof String) {
             SQLCharExpr charExpr = new SQLCharExpr((String) param);
             visit(charExpr);
-            return false;
+            return;
         }
 
         if (param instanceof Date) {
             print((Date) param);
-            return false;
+            return;
         }
 
         if (param instanceof InputStream) {
             print("'<InputStream>");
-            return false;
+            return;
         }
 
         if (param instanceof Reader) {
             print("'<Reader>");
-            return false;
+            return;
         }
 
         if (param instanceof Blob) {
             print("'<Blob>");
-            return false;
+            return;
         }
         
         if (param instanceof NClob) {
             print("'<NClob>");
-            return false;
+            return;
         }
 
         if (param instanceof Clob) {
             print("'<Clob>");
-            return false;
+            return;
         }
         
         print("'" + param.getClass().getName() + "'");
-        return false;
     }
 
     public boolean visit(SQLDropTableStatement x) {