improve sql parser

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

@@ -0,0 +1,29 @@
+package com.alibaba.druid.sql.ast.statement;
+
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.ast.SQLStatementImpl;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+
+public class SQLExplainStatement extends SQLStatementImpl {
+
+    protected SQLStatement statement;
+
+    public SQLStatement getStatement() {
+        return statement;
+    }
+
+    public void setStatement(SQLStatement statement) {
+        if (statement != null) {
+            statement.setParent(this);
+        }
+        this.statement = statement;
+    }
+
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, statement);
+        }
+        visitor.endVisit(this);
+    }
+}

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

@@ -35,7 +35,6 @@ import com.alibaba.druid.sql.ast.statement.SQLCharactorDataType;
 import com.alibaba.druid.sql.ast.statement.SQLColumnConstraint;
 import com.alibaba.druid.sql.ast.statement.SQLColumnDefinition;
 import com.alibaba.druid.sql.ast.statement.SQLCreateTableStatement;
-import com.alibaba.druid.sql.ast.statement.SQLDropUserStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.mysql.ast.MySqlForceIndexHint;

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleExplainStatement.java

@@ -15,27 +15,36 @@
  */
 package com.alibaba.druid.sql.dialect.oracle.ast.stmt;
 
+import com.alibaba.druid.sql.SQLUtils;
 import com.alibaba.druid.sql.ast.SQLExpr;
-import com.alibaba.druid.sql.ast.SQLStatement;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
+import com.alibaba.druid.sql.ast.statement.SQLExplainStatement;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class OracleExplainStatement extends OracleStatementImpl {
+public class OracleExplainStatement extends SQLExplainStatement implements OracleStatement {
 
-    private SQLCharExpr  statementId;
-    private SQLExpr      into;
-    private SQLStatement forStatement;
+    private SQLCharExpr statementId;
+    private SQLExpr     into;
 
     @Override
     public void accept0(OracleASTVisitor visitor) {
         if (visitor.visit(this)) {
             acceptChild(visitor, statementId);
             acceptChild(visitor, into);
-            acceptChild(visitor, forStatement);
+            acceptChild(visitor, statement);
         }
         visitor.endVisit(this);
     }
 
+    protected void accept0(SQLASTVisitor visitor) {
+        accept0((OracleASTVisitor) visitor);
+    }
+
+    public String toString() {
+        return SQLUtils.toOracleString(this);
+    }
+
     public SQLCharExpr getStatementId() {
         return statementId;
     }
@@ -52,12 +61,4 @@ public class OracleExplainStatement extends OracleStatementImpl {
         this.into = into;
     }
 
-    public SQLStatement getForStatement() {
-        return forStatement;
-    }
-
-    public void setForStatement(SQLStatement forStatement) {
-        this.forStatement = forStatement;
-    }
-
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleStatementParser.java

@@ -140,11 +140,6 @@ public class OracleStatementParser extends SQLStatementParser {
         }
     }
 
-    @Override
-    public void parseStatementList(List<SQLStatement> statementList) {
-        parseStatementList(statementList, -1);
-    }
-
     public void parseStatementList(List<SQLStatement> statementList, int max) {
         for (;;) {
             if (max != -1) {
@@ -298,12 +293,12 @@ public class OracleStatementParser extends SQLStatementParser {
                 continue;
             }
 
-            if (lexer.token() == Token.IDENTIFIER) {
-                if (identifierEquals("EXPLAIN")) {
-                    statementList.add(this.parseExplain());
-                    continue;
-                }
+            if (lexer.token() == Token.EXPLAIN) {
+                statementList.add(this.parseExplain());
+                continue;
+            }
 
+            if (lexer.token() == Token.IDENTIFIER) {
                 SQLExpr expr = exprParser.expr();
                 OracleExprStatement stmt = new OracleExprStatement(expr);
                 statementList.add(stmt);
@@ -470,7 +465,7 @@ public class OracleStatementParser extends SQLStatementParser {
                     statementList.add(stmt);
                     continue;
                 }
-                
+
                 if (lexer.token() == Token.TRIGGER) {
                     SQLDropTriggerStatement stmt = parseDropTrigger(false);
                     statementList.add(stmt);
@@ -1453,16 +1448,8 @@ public class OracleStatementParser extends SQLStatementParser {
         return clause;
     }
 
-    public SQLStatement parseStatement() {
-        List<SQLStatement> list = new ArrayList<SQLStatement>();
-
-        this.parseStatementList(list, 1);
-
-        return list.get(0);
-    }
-
     public OracleExplainStatement parseExplain() {
-        acceptIdentifier("EXPLAIN");
+        accept(Token.EXPLAIN);
         acceptIdentifier("PLAN");
         OracleExplainStatement stmt = new OracleExplainStatement();
 
@@ -1479,7 +1466,7 @@ public class OracleStatementParser extends SQLStatementParser {
         }
 
         accept(Token.FOR);
-        stmt.setForStatement(parseStatement());
+        stmt.setStatement(parseStatement());
 
         return stmt;
     }

src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleOutputVisitor.java

@@ -1882,7 +1882,7 @@ public class OracleOutputVisitor extends SQLASTOutputVisitor implements OracleAS
 
         print("FRO");
         println();
-        x.getForStatement().accept(this);
+        x.getStatement().accept(this);
 
         decrementIndent();
         return false;

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

@@ -58,6 +58,7 @@ public class Keywords {
         map.put("DISTINCT", Token.DISTINCT);
         map.put("DROP", Token.DROP);
         map.put("ELSE", Token.ELSE);
+        map.put("EXPLAIN", Token.EXPLAIN);
 
         map.put("END", Token.END);
         map.put("ESCAPE", Token.ESCAPE);

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

@@ -245,6 +245,7 @@ public class SQLExprParser extends SQLParser {
             case INITIALLY:
             case SEQUENCE:
             case USER:
+            case EXPLAIN:
                 sqlExpr = new SQLIdentifierExpr(lexer.stringVal());
                 lexer.nextToken();
                 break;

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

@@ -48,6 +48,7 @@ import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropTriggerStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropUserStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropViewStatement;
+import com.alibaba.druid.sql.ast.statement.SQLExplainStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLInsertInto;
 import com.alibaba.druid.sql.ast.statement.SQLInsertStatement;
@@ -89,7 +90,17 @@ public class SQLStatementParser extends SQLParser {
     }
 
     public void parseStatementList(List<SQLStatement> statementList) {
+        parseStatementList(statementList, -1);
+    }
+
+    public void parseStatementList(List<SQLStatement> statementList, int max) {
         for (;;) {
+            if (max != -1) {
+                if (statementList.size() >= max) {
+                    return;
+                }
+            }
+
             if (lexer.token() == Token.EOF) {
                 return;
             }
@@ -125,6 +136,11 @@ public class SQLStatementParser extends SQLParser {
                 statementList.add(parseDeleteStatement());
                 continue;
             }
+            
+            if (lexer.token() == (Token.EXPLAIN)) {
+                statementList.add(parseExplain());
+                continue;
+            }
 
             if (lexer.token() == Token.SET) {
                 statementList.add(parseSet());
@@ -587,7 +603,7 @@ public class SQLStatementParser extends SQLParser {
                 stmt.setCascade(Boolean.FALSE);
                 continue;
             }
-            
+
             break;
         }
 
@@ -1000,4 +1016,28 @@ public class SQLStatementParser extends SQLParser {
         }
         return item;
     }
+
+    public SQLStatement parseStatement() {
+        List<SQLStatement> list = new ArrayList<SQLStatement>();
+
+        this.parseStatementList(list, 1);
+
+        return list.get(0);
+    }
+
+    public SQLExplainStatement parseExplain() {
+        accept(Token.EXPLAIN);
+        if (identifierEquals("PLAN")) {
+            lexer.nextToken();
+        }
+        
+        if (lexer.token() == Token.FOR) {
+            lexer.nextToken();
+        }
+        
+        SQLExplainStatement explain = new SQLExplainStatement();
+        explain.setStatement(parseStatement());
+
+        return explain;
+    }
 }

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

@@ -22,6 +22,7 @@ package com.alibaba.druid.sql.parser;
  * @formatter:off
  */
 public enum Token {
+    EXPLAIN("EXPLAIN"), 
     FOR("FOR"), 
     IF("IF"), 
     INDEX("INDEX"), 

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

@@ -101,6 +101,7 @@ import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropTriggerStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropUserStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropViewStatement;
+import com.alibaba.druid.sql.ast.statement.SQLExplainStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprHint;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLForeignKeyConstraint;
@@ -1705,4 +1706,12 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Printab
         printAndAccept(x.getUsers(), ", ");
         return false;
     }
+    
+    @Override
+    public boolean visit(SQLExplainStatement x) {
+        print("EXPLAIN");
+        println();
+        x.getStatement().accept(this);
+        return false;
+    }
 }

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

@@ -85,6 +85,7 @@ import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropTriggerStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropUserStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropViewStatement;
+import com.alibaba.druid.sql.ast.statement.SQLExplainStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprHint;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLForeignKeyImpl;
@@ -499,4 +500,8 @@ public interface SQLASTVisitor {
     void endVisit(SQLDropUserStatement x);
 
     boolean visit(SQLDropUserStatement x);
+    
+    void endVisit(SQLExplainStatement x);
+    
+    boolean visit(SQLExplainStatement x);
 }

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

@@ -86,6 +86,7 @@ import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropTriggerStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropUserStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropViewStatement;
+import com.alibaba.druid.sql.ast.statement.SQLExplainStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprHint;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLForeignKeyImpl;
@@ -964,4 +965,14 @@ public class SQLASTVisitorAdapter implements SQLASTVisitor {
     public boolean visit(SQLDropUserStatement x) {
         return true;
     }
+    
+    @Override
+    public void endVisit(SQLExplainStatement x) {
+        
+    }
+    
+    @Override
+    public boolean visit(SQLExplainStatement x) {
+        return true;
+    }
 }

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlDescTest_0.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 1999-2011 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;
+
+import java.util.List;
+
+import org.junit.Assert;
+
+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.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+
+public class MySqlDescTest_0 extends MysqlTest {
+
+    public void test_0() throws Exception {
+        String sql = " Desc City";
+
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        stmt.accept(visitor);
+
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getColumns());
+        System.out.println("coditions : " + visitor.getConditions());
+        System.out.println("orderBy : " + visitor.getOrderByColumns());
+        
+        Assert.assertEquals(1, visitor.getTables().size());
+        Assert.assertEquals(0, visitor.getColumns().size());
+        Assert.assertEquals(0, visitor.getConditions().size());
+
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("City")));
+//        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("t2")));
+        
+//        Assert.assertTrue(visitor.getColumns().contains(new Column("t2", "id")));
+    }
+}

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

@@ -32,13 +32,13 @@ public class MySqlDescribteTest extends MysqlTest {
 
         MySqlStatementParser parser = new MySqlStatementParser(sql);
         List<SQLStatement> statementList = parser.parseStatementList();
-        SQLStatement statemen = statementList.get(0);
+        SQLStatement stmt = statementList.get(0);
         print(statementList);
 
         Assert.assertEquals(1, statementList.size());
 
         MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
-        statemen.accept(visitor);
+        stmt.accept(visitor);
 
         System.out.println("Tables : " + visitor.getTables());
         System.out.println("fields : " + visitor.getColumns());

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlExplainTest_0.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 1999-2011 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;
+
+import java.util.List;
+
+import org.junit.Assert;
+
+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.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+
+public class MySqlExplainTest_0 extends MysqlTest {
+
+    public void test_0() throws Exception {
+        String sql = "explain SELECT * FROM sonar.groups where id = 1";
+
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        stmt.accept(visitor);
+
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getColumns());
+        System.out.println("coditions : " + visitor.getConditions());
+        System.out.println("orderBy : " + visitor.getOrderByColumns());
+        
+        Assert.assertEquals(1, visitor.getTables().size());
+        Assert.assertEquals(2, visitor.getColumns().size());
+        Assert.assertEquals(1, visitor.getConditions().size());
+
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("sonar.groups")));
+//        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("t2")));
+        
+//        Assert.assertTrue(visitor.getColumns().contains(new Column("t2", "id")));
+    }
+}

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlSetTest_0.java

@@ -30,14 +30,14 @@ public class MySqlSetTest_0 extends MysqlTest {
         String sql = "SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ";
 
         MySqlStatementParser parser = new MySqlStatementParser(sql);
-        List<SQLStatement> stmt = parser.parseStatementList();
-        SQLStatement statemen = stmt.get(0);
-        print(stmt);
+        List<SQLStatement> stmtList = parser.parseStatementList();
+        SQLStatement stmt = stmtList.get(0);
+        print(stmtList);
 
-        Assert.assertEquals(1, stmt.size());
+        Assert.assertEquals(1, stmtList.size());
 
         MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
-        statemen.accept(visitor);
+        stmt.accept(visitor);
 
         System.out.println("Tables : " + visitor.getTables());
         System.out.println("fields : " + visitor.getColumns());
@@ -48,7 +48,7 @@ public class MySqlSetTest_0 extends MysqlTest {
         Assert.assertEquals(0, visitor.getColumns().size());
         Assert.assertEquals(0, visitor.getConditions().size());
 
-        String text = output(stmt);
+        String text = output(stmtList);
 
         Assert.assertEquals("SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ", text);
     }