bug fixed for issue #2582

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlStatementParser.java

@@ -4101,8 +4101,18 @@ public class MySqlStatementParser extends SQLStatementParser {
             stmt.addItem(dropPartition);
         } else if (lexer.token() == Token.IDENTIFIER) {
             SQLAlterTableDropColumnItem item = new SQLAlterTableDropColumnItem();
-            this.exprParser.names(item.getColumns());
+
+            SQLName name = this.exprParser.name();
+            item.addColumn(name);
             stmt.addItem(item);
+
+            if (lexer.token() == Token.COMMA) {
+                lexer.nextToken();
+            }
+
+            if (lexer.token() == Token.DROP) {
+                parseAlterDrop(stmt);
+            }
         } else {
             super.parseAlterDrop(stmt);
         }

src/test/java/com/alibaba/druid/bvt/sql/mysql/alter/MySqlAlterTableDrop_Test_1.java

@@ -0,0 +1,42 @@
+/*
+ * 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.alter;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
+import com.alibaba.druid.sql.parser.Token;
+import junit.framework.TestCase;
+import org.junit.Assert;
+
+public class MySqlAlterTableDrop_Test_1 extends TestCase {
+
+    public void test_alter_first() throws Exception {
+        String sql = "ALTER TABLE test.student DROP Column9, DROP Column10;";
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        SQLStatement stmt = parser.parseStatementList().get(0);
+        parser.match(Token.EOF);
+        
+        assertEquals("ALTER TABLE test.student\n" +
+                "\tDROP COLUMN Column9,\n" +
+                "\tDROP COLUMN Column10;", SQLUtils.toMySqlString(stmt));
+        
+        assertEquals("alter table test.student\n" +
+                "\tdrop column Column9,\n" +
+                "\tdrop column Column10;", SQLUtils.toMySqlString(stmt, SQLUtils.DEFAULT_LCASE_FORMAT_OPTION));
+    }
+
+}