refactor && enhance mysql sql parser support

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/expr/MySqlBinaryExpr.java

@@ -19,7 +19,7 @@ import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class MySqlBinaryExpr extends SQLLiteralExpr implements MySqlExpr {
+public class MySqlBinaryExpr extends MySqlExprImpl implements MySqlExpr, SQLLiteralExpr {
 
     private static final long serialVersionUID = 1L;
 
@@ -47,7 +47,7 @@ public class MySqlBinaryExpr extends SQLLiteralExpr implements MySqlExpr {
         this.accept0((MySqlASTVisitor) visitor);
     }
 
-    protected void accept0(MySqlASTVisitor visitor) {
+    public void accept0(MySqlASTVisitor visitor) {
         visitor.visit(this);
 
         visitor.endVisit(this);

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/expr/MySqlBooleanExpr.java

@@ -19,7 +19,7 @@ import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class MySqlBooleanExpr extends SQLLiteralExpr implements MySqlExpr {
+public class MySqlBooleanExpr extends MySqlExprImpl implements MySqlExpr, SQLLiteralExpr {
 
     private static final long serialVersionUID = 1L;
 
@@ -46,7 +46,7 @@ public class MySqlBooleanExpr extends SQLLiteralExpr implements MySqlExpr {
         this.accept0((MySqlASTVisitor) visitor);
     }
 
-    protected void accept0(MySqlASTVisitor visitor) {
+    public void accept0(MySqlASTVisitor visitor) {
         visitor.visit(this);
 
         visitor.endVisit(this);

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/expr/MySqlExprImpl.java

@@ -0,0 +1,10 @@
+package com.alibaba.druid.sql.dialect.mysql.ast.expr;
+
+import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.dialect.mysql.ast.MySqlObjectImpl;
+
+public abstract class MySqlExprImpl extends MySqlObjectImpl implements SQLExpr {
+
+    private static final long serialVersionUID = 1L;
+
+}

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/expr/MySqlHexadecimalExpr.java

@@ -0,0 +1,16 @@
+package com.alibaba.druid.sql.dialect.mysql.ast.expr;
+
+import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
+
+
+public class MySqlHexadecimalExpr extends MySqlExprImpl implements SQLLiteralExpr {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public void accept0(MySqlASTVisitor visitor) {
+        
+    }
+
+}

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/statement/MySqlSetTransactionIsolationLevelStatement.java

@@ -0,0 +1,34 @@
+package com.alibaba.druid.sql.dialect.mysql.ast.statement;
+
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
+
+public class MySqlSetTransactionIsolationLevelStatement extends MySqlStatementImpl {
+
+    private static final long serialVersionUID = 1L;
+
+    private Boolean           global;
+
+    private String            level;
+
+    public String getLevel() {
+        return level;
+    }
+
+    public void setLevel(String level) {
+        this.level = level;
+    }
+
+    public void accept0(MySqlASTVisitor visitor) {
+        visitor.visit(this);
+        visitor.endVisit(this);
+    }
+
+    public Boolean getGlobal() {
+        return global;
+    }
+
+    public void setGlobal(Boolean global) {
+        this.global = global;
+    }
+
+}

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

@@ -24,6 +24,7 @@ import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
 import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
+import com.alibaba.druid.sql.ast.statement.SQLAssignItem;
 import com.alibaba.druid.sql.ast.statement.SQLColumnDefinition;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBooleanExpr;
@@ -132,6 +133,21 @@ public class MySqlExprParser extends SQLExprParser {
                 String aliasValue = lexer.stringVal();
                 lexer.nextToken();
                 return primaryRest(new SQLCharExpr(aliasValue));
+            case VARIANT:
+                SQLVariantRefExpr varRefExpr = new SQLVariantRefExpr(lexer.stringVal());
+                lexer.nextToken();
+                if (varRefExpr.getName().equalsIgnoreCase("@@global")) {
+                    accept(Token.DOT);
+                    varRefExpr = new SQLVariantRefExpr(lexer.stringVal(), true);
+                    lexer.nextToken();
+                } else if (varRefExpr.getName().equals("@") && lexer.token() == Token.LITERAL_CHARS) {
+                    varRefExpr.setName("@'" + lexer.stringVal() + "'");
+                    lexer.nextToken();
+                } else if (varRefExpr.getName().equals("@@") && lexer.token() == Token.LITERAL_CHARS) {
+                    varRefExpr.setName("@@'" + lexer.stringVal() + "'");
+                    lexer.nextToken();
+                } 
+                return primaryRest(varRefExpr);
             default:
                 return super.primary();
         }
@@ -496,4 +512,35 @@ public class MySqlExprParser extends SQLExprParser {
 
         return expr;
     }
+    
+    public SQLAssignItem parseAssignItem() {
+        SQLAssignItem item = new SQLAssignItem();
+        
+        SQLExpr var = primary();
+        
+        if (var instanceof SQLIdentifierExpr) {
+            String ident = ((SQLIdentifierExpr) var).getName();
+            
+            if ("GLOBAL".equalsIgnoreCase(ident)) {
+                ident = lexer.stringVal();
+                lexer.nextToken();
+                var = new SQLVariantRefExpr(ident, true);
+            } else if ("SESSION".equalsIgnoreCase(ident)) {
+                    ident = lexer.stringVal();
+                    lexer.nextToken();
+                    var = new SQLVariantRefExpr(ident, false);
+            } else {
+                var = new SQLVariantRefExpr(ident);
+            }
+        }
+        item.setTarget(var);
+        if (lexer.token() == Token.COLONEQ) {
+            lexer.nextToken();
+        } else {
+            accept(Token.EQ);
+        }
+        item.setValue(expr());
+
+        return item;
+    }
 }

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

@@ -95,7 +95,6 @@ public class MySqlLexer extends Lexer {
         map.put("CAST", Token.CAST);
         map.put("IN", Token.IN);
         map.put("ASC", Token.ASC);
-        map.put("DESC", Token.DESC);
         map.put("LIKE", Token.LIKE);
         map.put("ESCAPE", Token.ESCAPE);
         map.put("BETWEEN", Token.BETWEEN);
@@ -128,6 +127,71 @@ public class MySqlLexer extends Lexer {
         super.keywods = DEFAULT_MYSQL_KEYWORDS;
     }
 
+    public void scanVariable() {
+        final char first = ch;
+
+        if (ch != '@' && ch != ':' && ch != '#') {
+            throw new SQLParseException("illegal variable");
+        }
+
+        int hash = first;
+
+        np = bp;
+        sp = 1;
+
+        if (buf[bp + 1] == '@') {
+            ch = buf[++bp];
+            hash = 31 * hash + ch;
+
+            sp++;
+        }
+
+        if (buf[bp + 1] == '`') {
+            ++bp;
+            ++sp;
+            char ch;
+            for (;;) {
+                ch = buf[++bp];
+
+                if (ch == '`') {
+                    sp++;
+                    ch = buf[++bp];
+                    break;
+                } else if (ch == EOI) {
+                    throw new SQLParseException("illegal identifier");
+                }
+
+                hash = 31 * hash + ch;
+
+                sp++;
+                continue;
+            }
+
+            this.ch = buf[bp];
+
+            stringVal = symbolTable.addSymbol(buf, np, sp, hash);
+            token = Token.VARIANT;
+        } else {
+            for (;;) {
+                ch = buf[++bp];
+
+                if (!isIdentifierChar(ch)) {
+                    break;
+                }
+
+                hash = 31 * hash + ch;
+
+                sp++;
+                continue;
+            }
+        }
+
+        this.ch = buf[bp];
+
+        stringVal = symbolTable.addSymbol(buf, np, sp, hash);
+        token = Token.VARIANT;
+    }
+
     public void scanIdentifier() {
         final char first = ch;
 

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

@@ -25,10 +25,12 @@ import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.ast.expr.SQLQueryExpr;
+import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
 import com.alibaba.druid.sql.ast.statement.SQLCreateTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLInsertStatement;
 import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
+import com.alibaba.druid.sql.ast.statement.SQLSetStatement;
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
@@ -50,6 +52,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlReplicateStatement
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlResetStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlRollbackStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSetTransactionIsolationLevelStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowColumnsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowDatabasesStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowStatusStatement;
@@ -84,11 +87,11 @@ public class MySqlStatementParser extends SQLStatementParser {
     public SQLSelectStatement parseSelect() throws ParserException {
         return new SQLSelectStatement(new MySqlSelectParser(lexer).select());
     }
-    
+
     public SQLUpdateStatement parseUpdateStatement() throws ParserException {
-    	MySqlUpdateStatement stmt = (MySqlUpdateStatement) super.parseUpdateStatement();
-    	
-    	if (lexer.token() == Token.LIMIT) {
+        MySqlUpdateStatement stmt = (MySqlUpdateStatement) super.parseUpdateStatement();
+
+        if (lexer.token() == Token.LIMIT) {
             lexer.nextToken();
 
             MySqlSelectQueryBlock.Limit limit = new MySqlSelectQueryBlock.Limit();
@@ -105,16 +108,16 @@ public class MySqlStatementParser extends SQLStatementParser {
             } else {
                 limit.setRowCount(temp);
             }
-            
+
             stmt.setLimit(limit);
-    	}
-    	
-    	return stmt;
+        }
+
+        return stmt;
+    }
+
+    protected MySqlUpdateStatement createUpdateStatement() {
+        return new MySqlUpdateStatement();
     }
-    
-	protected MySqlUpdateStatement createUpdateStatement() {
-		return new MySqlUpdateStatement();
-	}
 
     public MySqlDeleteStatement parseDeleteStatement() throws ParserException {
         MySqlDeleteStatement deleteStatement = new MySqlDeleteStatement();
@@ -375,7 +378,7 @@ public class MySqlStatementParser extends SQLStatementParser {
             return true;
         }
 
-        if (identifierEquals("DESCRIBE")) {
+        if (identifierEquals("DESC") || identifierEquals("DESCRIBE")) {
             SQLStatement stmt = parseDescribe();
             statementList.add(stmt);
             return true;
@@ -384,8 +387,12 @@ public class MySqlStatementParser extends SQLStatementParser {
         return false;
     }
 
-    public SQLStatement parseDescribe() throws ParserException {
-        acceptIdentifier("DESCRIBE");
+    public MySqlDescribeStatement parseDescribe() throws ParserException {
+        if (identifierEquals("DESC") || identifierEquals("DESCRIBE")) {
+            lexer.nextToken();
+        } else {
+            throw new ParserException("expect DESC, actual " + lexer.token());
+        }
 
         MySqlDescribeStatement stmt = new MySqlDescribeStatement();
         stmt.setObject(this.exprParser.name());
@@ -1067,4 +1074,72 @@ public class MySqlStatementParser extends SQLStatementParser {
     public SQLSelectParser createSQLSelectParser() {
         return new MySqlSelectParser(this.lexer);
     }
+
+    public SQLStatement parseSet() throws ParserException {
+        accept(Token.SET);
+
+        Boolean global = null;
+        if (identifierEquals("GLOBAL")) {
+            global = Boolean.TRUE;
+            lexer.nextToken();
+        } else if (identifierEquals("SESSION")) {
+            global = Boolean.FALSE;
+            lexer.nextToken();
+        }
+
+        if (identifierEquals("TRANSACTION")) {
+            lexer.nextToken();
+            acceptIdentifier("ISOLATION");
+            acceptIdentifier("LEVEL");
+            
+            MySqlSetTransactionIsolationLevelStatement stmt = new MySqlSetTransactionIsolationLevelStatement();
+            stmt.setGlobal(global);
+            
+            if (identifierEquals("READ")) {
+                lexer.nextToken();
+                
+                if (identifierEquals("UNCOMMITTED")) {
+                    stmt.setLevel("READ UNCOMMITTED");
+                    lexer.nextToken();
+                } else if (identifierEquals("WRITE")) {
+                    stmt.setLevel("READ WRITE");
+                    lexer.nextToken();
+                } else if (identifierEquals("ONLY")) {
+                    stmt.setLevel("READ ONLY");
+                    lexer.nextToken();
+                } else if (identifierEquals("COMMITTED")) {
+                    stmt.setLevel("READ COMMITTED");
+                    lexer.nextToken();
+                } else {
+                    throw new ParserException("UNKOWN TRANSACTION LEVEL : " + lexer.stringVal());
+                }
+            } else if (identifierEquals("SERIALIZABLE")) {
+                stmt.setLevel("SERIALIZABLE");
+                lexer.nextToken();
+            } else if (identifierEquals("REPEATABLE")) {
+                lexer.nextToken();
+                if (identifierEquals("READ")) {
+                    stmt.setLevel("REPEATABLE READ");
+                    lexer.nextToken();
+                } else {
+                    throw new ParserException("UNKOWN TRANSACTION LEVEL : " + lexer.stringVal());
+                }
+            } else {
+                throw new ParserException("UNKOWN TRANSACTION LEVEL : " + lexer.stringVal());
+            }
+            
+            return stmt;
+        } else {
+            SQLSetStatement stmt = new SQLSetStatement();
+
+            parseAssignItems(stmt.getItems());
+            
+            if (global != null && global.booleanValue()) {
+                SQLVariantRefExpr varRef = (SQLVariantRefExpr) stmt.getItems().get(0).getTarget();
+                varRef.setGlobal(true);
+            }
+
+            return stmt;
+        }
+    }
 }

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

@@ -43,6 +43,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlResetStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlRollbackStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectGroupBy;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSetTransactionIsolationLevelStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowColumnsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowDatabasesStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowStatusStatement;
@@ -206,4 +207,8 @@ public interface MySqlASTVisitor extends SQLASTVisitor {
     boolean visit(MySqlUpdateStatement x);
     
     void endVisit(MySqlUpdateStatement x);
+    
+    boolean visit(MySqlSetTransactionIsolationLevelStatement x);
+    
+    void endVisit(MySqlSetTransactionIsolationLevelStatement x);
 }

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

@@ -30,6 +30,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlRollbackStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectGroupBy;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSetTransactionIsolationLevelStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowColumnsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowDatabasesStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowStatusStatement;
@@ -444,4 +445,14 @@ public class MySqlASTVisitorAdapter extends SQLASTVisitorAdapter implements
 		
 	}
 
+    @Override
+    public boolean visit(MySqlSetTransactionIsolationLevelStatement x) {
+        return true;
+    }
+
+    @Override
+    public void endVisit(MySqlSetTransactionIsolationLevelStatement x) {
+        
+    }
+
 }

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

@@ -62,6 +62,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSQLColumnDefinitio
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectGroupBy;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSetTransactionIsolationLevelStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowColumnsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowDatabasesStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowStatusStatement;
@@ -100,7 +101,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         if (x.getOrderBy() != null) {
             x.getOrderBy().setParent(x);
         }
-        
+
         print("SELECT ");
 
         if (SQLSetQuantifier.ALL == x.getDistionOption()) print("ALL ");
@@ -425,7 +426,30 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
     }
 
     public boolean visit(SQLVariantRefExpr x) {
-        print(x.getName());
+        if (x.isGlobal()) {
+            print("@@global.");
+        } else {
+            if ((!x.getName().startsWith("@")) && (!x.getName().equals("?"))) {
+                print("@@");
+            }
+        }
+
+        for (int i = 0; i < x.getName().length(); ++i) {
+            char ch = x.getName().charAt(i);
+            if (ch == '\'') {
+                if (x.getName().startsWith("@@") && i == 2) {
+                    print(ch);
+                } else if (x.getName().startsWith("@") && i == 1) {
+                    print(ch);
+                } else if (i != 0 && i != x.getName().length() - 1) {
+                    print("\\'");
+                } else {
+                    print(ch);
+                }
+            } else {
+                print(ch);
+            }
+        }
 
         String collate = (String) x.getAttribute("COLLATE");
         if (collate != null) {
@@ -1250,12 +1274,12 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
     @Override
     public boolean visit(UserSpecification x) {
         x.getUser().accept(this);
-        
+
         if (x.getPassword() != null) {
             print(" IDENTIFIED BY ");
             x.getPassword().accept(this);
         }
-        
+
         if (x.getAuthPlugin() != null) {
             print(" IDENTIFIED WITH ");
             x.getAuthPlugin().accept(this);
@@ -1265,7 +1289,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public void endVisit(MySqlDropUser x) {
-        
+
     }
 
     @Override
@@ -1277,7 +1301,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public void endVisit(MySqlDropTableStatement x) {
-        
+
     }
 
     @Override
@@ -1286,14 +1310,14 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         if (x.isIfExists()) {
             print("IF EXISTS ");
         }
-        
+
         printAndAccept(x.getTableSources(), ", ");
         return false;
     }
 
     @Override
     public void endVisit(MySqlPartitionByKey x) {
-        
+
     }
 
     @Override
@@ -1301,7 +1325,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         print("PARTITION BY KEY (");
         printAndAccept(x.getColumns(), ", ");
         print(")");
-        
+
         if (x.getPartitionCount() != null) {
             print(" PARTITIONS ");
             x.getPartitionCount().accept(this);
@@ -1311,21 +1335,20 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
 
     @Override
     public void endVisit(MySqlSelectQueryBlock x) {
-        
+
     }
 
     @Override
     public boolean visit(MySqlOutFileExpr x) {
         print("OUTFILE ");
         x.getFile().accept(this);
-        
+
         if (x.getCharset() != null) {
             print(" CHARACTER SET ");
             print(x.getCharset());
         }
 
-        if (x.getColumnsTerminatedBy() != null || x.getColumnsEnclosedBy() != null
-            || x.getColumnsEscaped() != null) {
+        if (x.getColumnsTerminatedBy() != null || x.getColumnsEnclosedBy() != null || x.getColumnsEscaped() != null) {
             print(" COLUMNS");
             if (x.getColumnsTerminatedBy() != null) {
                 print(" TERMINATED BY ");
@@ -1358,39 +1381,56 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
                 x.getLinesTerminatedBy().accept(this);
             }
         }
-        
+
         return false;
     }
 
     @Override
     public void endVisit(MySqlOutFileExpr x) {
-        
+
     }
 
     @Override
     public boolean visit(MySqlDescribeStatement x) {
-        print("DESCRIBE ");
+        print("DESC ");
         x.getObject().accept(this);
         return false;
     }
 
     @Override
     public void endVisit(MySqlDescribeStatement x) {
-        
+
     }
 
-	@Override
-	public boolean visit(MySqlUpdateStatement x) {
-		super.visit((SQLUpdateStatement) x);
-		if (x.getLimit() != null) {
-			println();
-			x.getLimit().accept(this);
-		}
-		return false;
-	}
+    @Override
+    public boolean visit(MySqlUpdateStatement x) {
+        super.visit((SQLUpdateStatement) x);
+        if (x.getLimit() != null) {
+            println();
+            x.getLimit().accept(this);
+        }
+        return false;
+    }
 
-	@Override
-	public void endVisit(MySqlUpdateStatement x) {
-		
-	}
+    @Override
+    public void endVisit(MySqlUpdateStatement x) {
+
+    }
+
+    @Override
+    public boolean visit(MySqlSetTransactionIsolationLevelStatement x) {
+        return false;
+    }
+
+    @Override
+    public void endVisit(MySqlSetTransactionIsolationLevelStatement x) {
+        if (x.getGlobal() == null) {
+            print("SET TRANSACTION ISOLATION LEVEL ");
+        } else if (x.getGlobal().booleanValue()) {
+            print("SET GLOBAL TRANSACTION ISOLATION LEVEL ");
+        } else {
+            print("SET SESSION TRANSACTION ISOLATION LEVEL ");
+        }
+        print(x.getLevel());
+    }
 }

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

@@ -39,6 +39,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlRollbackStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectGroupBy;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSetTransactionIsolationLevelStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowColumnsStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowDatabasesStatement;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlShowStatusStatement;
@@ -505,4 +506,14 @@ public class MySqlSchemaStatVisitor extends SchemaStatVisitor implements MySqlAS
 	public void endVisit(MySqlUpdateStatement x) {
 		
 	}
+
+    @Override
+    public boolean visit(MySqlSetTransactionIsolationLevelStatement x) {
+        return false;
+    }
+
+    @Override
+    public void endVisit(MySqlSetTransactionIsolationLevelStatement x) {
+        
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/expr/OracleDateExpr.java

@@ -15,11 +15,12 @@
  */
 package com.alibaba.druid.sql.dialect.oracle.ast.expr;
 
+import com.alibaba.druid.sql.ast.SQLExprImpl;
 import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class OracleDateExpr extends SQLLiteralExpr implements OracleExpr {
+public class OracleDateExpr extends SQLExprImpl implements SQLLiteralExpr, OracleExpr {
 
     private static final long serialVersionUID = 1L;
 

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/expr/OracleIntervalExpr.java

@@ -16,11 +16,12 @@
 package com.alibaba.druid.sql.dialect.oracle.ast.expr;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLExprImpl;
 import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class OracleIntervalExpr extends SQLLiteralExpr implements OracleExpr {
+public class OracleIntervalExpr extends SQLExprImpl implements SQLLiteralExpr, OracleExpr {
 
     private static final long  serialVersionUID = 1L;
     private SQLExpr            value;

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/expr/OracleTimestampExpr.java

@@ -15,11 +15,12 @@
  */
 package com.alibaba.druid.sql.dialect.oracle.ast.expr;
 
+import com.alibaba.druid.sql.ast.SQLExprImpl;
 import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class OracleTimestampExpr extends SQLLiteralExpr implements OracleExpr {
+public class OracleTimestampExpr extends SQLExprImpl implements SQLLiteralExpr, OracleExpr {
 
     private static final long serialVersionUID = 1L;
     private String            literal;