From c451043c82b439670699c26200db6487ecaec425 Mon Sep 17 00:00:00 2001
From: wenshao <szujobs@hotmail.com>
Date: Tue, 26 Dec 2017 11:24:36 +0800
Subject: [PATCH] add exists syntax check.

---
 .../druid/sql/parser/SQLExprParser.java       |  6 +++
 .../java/com/alibaba/druid/util/FnvHash.java  |  1 +
 .../select/MySqlSelectTest_94_error.java      | 39 +++++++++++++++++++
 3 files changed, 46 insertions(+)
 create mode 100644 src/test/java/com/alibaba/druid/bvt/sql/mysql/select/MySqlSelectTest_94_error.java

diff --git a/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java b/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java
index 9935bd1159..82bc4633ea 100644
--- a/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java
+++ b/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java
@@ -1064,6 +1064,12 @@ public class SQLExprParser extends SQLParser {
             exprList(methodInvokeExpr.getParameters(), methodInvokeExpr);
         }
 
+        if (hash_lower == FnvHash.Constants.EXIST
+                && methodInvokeExpr.getParameters().size() == 1
+                && methodInvokeExpr.getParameters().get(0) instanceof SQLQueryExpr) {
+            throw new ParserException("exists syntax error.");
+        }
+
         if (lexer.token == Token.FROM) {
             lexer.nextToken();
             SQLExpr from = this.expr();
diff --git a/src/main/java/com/alibaba/druid/util/FnvHash.java b/src/main/java/com/alibaba/druid/util/FnvHash.java
index f1f888871d..7733b8322e 100644
--- a/src/main/java/com/alibaba/druid/util/FnvHash.java
+++ b/src/main/java/com/alibaba/druid/util/FnvHash.java
@@ -629,5 +629,6 @@ public final class FnvHash {
         long BUILD = fnv1a_64_lower("BUILD");
         long NOCACHE = fnv1a_64_lower("NOCACHE");
         long NOPARALLEL = fnv1a_64_lower("NOPARALLEL");
+        long EXIST = fnv1a_64_lower("EXIST");
     }
 }
diff --git a/src/test/java/com/alibaba/druid/bvt/sql/mysql/select/MySqlSelectTest_94_error.java b/src/test/java/com/alibaba/druid/bvt/sql/mysql/select/MySqlSelectTest_94_error.java
new file mode 100644
index 0000000000..74c0123740
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/bvt/sql/mysql/select/MySqlSelectTest_94_error.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright 1999-2017 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.bvt.sql.mysql.select;
+
+import com.alibaba.druid.sql.MysqlTest;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
+import com.alibaba.druid.sql.parser.ParserException;
+
+import java.util.List;
+
+public class MySqlSelectTest_94_error extends MysqlTest {
+
+    public void test_0() throws Exception {
+        String sql = "select * from ttt where exist (select max(id) from ttt);";
+
+        Exception error = null;
+        try {
+            MySqlStatementParser parser = new MySqlStatementParser(sql);
+            List<SQLStatement> statementList = parser.parseStatementList();
+        } catch (ParserException ex) {
+            error = ex;
+        }
+        assertNotNull(error);
+    }
+}