bug fixed for sql parser. issue #1507

src/main/java/com/alibaba/druid/sql/dialect/odps/ast/OdpsSelectQueryBlock.java

@@ -79,9 +79,10 @@ public class OdpsSelectQueryBlock extends SQLSelectQueryBlock {
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj) return true;
-        if (obj == null) return false;
-        if (getClass() != obj.getClass()) return false;
+        if (!super.equals(obj)) {
+            return false;
+        }
+
         OdpsSelectQueryBlock other = (OdpsSelectQueryBlock) obj;
         if (limit == null) {
             if (other.limit != null) return false;

src/test/java/com/alibaba/druid/bvt/sql/EqualTest_select.java

@@ -0,0 +1,24 @@
+package com.alibaba.druid.bvt.sql;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.expr.SQLAnyExpr;
+import com.alibaba.druid.sql.ast.statement.SQLSelect;
+import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
+import com.alibaba.druid.sql.dialect.oracle.parser.OracleExprParser;
+import com.alibaba.druid.util.JdbcConstants;
+import junit.framework.TestCase;
+import org.junit.Assert;
+
+import java.util.List;
+
+public class EqualTest_select extends TestCase {
+
+    public void test_eq_select() throws Exception {
+        List stmtsA = SQLUtils.parseStatements("select * from a", JdbcConstants.ODPS);
+        List stmtsB = SQLUtils.parseStatements("select * from b", JdbcConstants.ODPS);
+        SQLSelect selectA = ((SQLSelectStatement) stmtsA.get(0)).getSelect();
+        SQLSelect selectB = ((SQLSelectStatement) stmtsB.get(0)).getSelect();
+        boolean eq = selectA.equals(selectB);
+        assertFalse(eq);
+    }
+}