bugfix:union子查询bug

src/main/java/com/alibaba/druid/sql/ast/statement/SQLUnionQueryTableSource.java

@@ -0,0 +1,50 @@
+package com.alibaba.druid.sql.ast.statement;
+
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+public class SQLUnionQueryTableSource extends SQLTableSourceImpl {
+
+    private SQLUnionQuery union;
+
+    public SQLUnionQueryTableSource(){
+
+    }
+
+    public SQLUnionQueryTableSource(String alias){
+        super(alias);
+    }
+
+    public SQLUnionQueryTableSource(SQLUnionQuery union, String alias){
+        super(alias);
+        this.setUnion(union);
+    }
+
+    public SQLUnionQueryTableSource(SQLUnionQuery union){
+        this.setUnion(union);
+    }
+
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, union);
+        }
+        visitor.endVisit(this);
+    }
+
+    public void output(StringBuffer buf) {
+        buf.append("(");
+        this.union.output(buf);
+        buf.append(")");
+    }
+
+    public SQLUnionQuery getUnion() {
+        return union;
+    }
+
+    public void setUnion(SQLUnionQuery union) {
+        if (union != null) {
+            union.setParent(this);
+        }
+        this.union = union;
+    }
+}

src/main/java/com/alibaba/druid/sql/parser/SQLSelectParser.java

@@ -32,6 +32,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSubqueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLUnionOperator;
 import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
+import com.alibaba.druid.sql.ast.statement.SQLUnionQueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLWithSubqueryClause;
 
 public class SQLSelectParser extends SQLParser {
@@ -316,8 +317,12 @@ public class SQLSelectParser extends SQLParser {
             if (lexer.token() == Token.SELECT || lexer.token() == Token.WITH) {
                 SQLSelect select = select();
                 accept(Token.RPAREN);
-                queryRest(select.getQuery());
-                tableSource = new SQLSubqueryTableSource(select);
+                SQLSelectQuery query = queryRest(select.getQuery());
+                if (query instanceof SQLUnionQuery) {
+                    tableSource = new SQLUnionQueryTableSource((SQLUnionQuery) query);
+                } else {
+                    tableSource = new SQLSubqueryTableSource(select);
+                }
             } else if (lexer.token() == Token.LPAREN) {
                 tableSource = parseTableSource();
                 accept(Token.RPAREN);

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

@@ -136,6 +136,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSubqueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLTableElement;
 import com.alibaba.druid.sql.ast.statement.SQLTruncateStatement;
 import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
+import com.alibaba.druid.sql.ast.statement.SQLUnionQueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLUnique;
 import com.alibaba.druid.sql.ast.statement.SQLUniqueConstraint;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
@@ -1975,4 +1976,21 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Printab
 
     public void endVisit(SQLBooleanExpr x) {
     }
+    
+    @Override
+    public boolean visit(SQLUnionQueryTableSource x) {
+        print("(");
+        incrementIndent();
+        x.getUnion().accept(this);
+        println();
+        decrementIndent();
+        print(")");
+
+        if (x.getAlias() != null) {
+            print(' ');
+            print(x.getAlias());
+        }
+
+        return false;
+    }
 }

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

@@ -112,6 +112,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSetStatement;
 import com.alibaba.druid.sql.ast.statement.SQLSubqueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLTruncateStatement;
 import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
+import com.alibaba.druid.sql.ast.statement.SQLUnionQueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLUnique;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
@@ -540,4 +541,8 @@ public interface SQLASTVisitor {
     
     boolean visit(SQLBooleanExpr x);
     
+    void endVisit(SQLUnionQueryTableSource x);
+
+    boolean visit(SQLUnionQueryTableSource x);
+    
 }

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

@@ -114,6 +114,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSetStatement;
 import com.alibaba.druid.sql.ast.statement.SQLSubqueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLTruncateStatement;
 import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
+import com.alibaba.druid.sql.ast.statement.SQLUnionQueryTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLUnique;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
@@ -1053,4 +1054,14 @@ public class SQLASTVisitorAdapter implements SQLASTVisitor {
         return true;
     }
     
+    @Override
+    public void endVisit(SQLUnionQueryTableSource x) {
+        
+    }
+
+    @Override
+    public boolean visit(SQLUnionQueryTableSource x) {
+        return true;
+    }
+    
 }

src/test/java/com/alibaba/druid/bvt/sql/mysql/SQLSelectTest.java

@@ -88,6 +88,15 @@ public class SQLSelectTest extends TestCase {
 
         output(stmtList);
     }
+    
+    public void test_select_7() throws Exception {
+        String sql = "select * from ((select * from test1) UNION (select * from test2) UNION (select * from test3)) where t1='温高铁';";
+
+        SQLStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> stmtList = parser.parseStatementList();
+
+        output(stmtList);
+    }
 
     private void output(List<SQLStatement> stmtList) {
         for (SQLStatement stmt : stmtList) {