improve sql-wal

src/main/java/com/alibaba/druid/sql/ast/expr/SQLUnaryExpr.java

@@ -52,12 +52,6 @@ public class SQLUnaryExpr extends SQLExprImpl implements Serializable {
         this.expr = expr;
     }
 
-    @Override
-    public void output(StringBuffer buf) {
-        buf.append(" NOT ");
-        this.expr.output(buf);
-    }
-
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
             acceptChild(visitor, this.expr);

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

@@ -30,7 +30,7 @@ public class SQLColumnDefinition extends SQLObjectImpl implements SQLTableElemen
     protected SQLDataType                     dataType;
     protected SQLExpr                         defaultExpr;
     protected final List<SQLColumnConstraint> constaints = new ArrayList<SQLColumnConstraint>(0);
-    protected String                          comment;
+    protected SQLExpr                          comment;
 
     protected Boolean                         enable;
 
@@ -99,11 +99,11 @@ public class SQLColumnDefinition extends SQLObjectImpl implements SQLTableElemen
         visitor.endVisit(this);
     }
 
-    public String getComment() {
+    public SQLExpr getComment() {
         return comment;
     }
 
-    public void setComment(String comment) {
+    public void setComment(SQLExpr comment) {
         this.comment = comment;
     }
 

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2EvalVisitor.java

@@ -135,7 +135,7 @@ public class DB2EvalVisitor extends DB2ASTVisitorAdapter implements SQLEvalVisit
     public void registerFunction(String funcName, Function function) {
         functions.put(funcName, function);
     }
-    
+
     public boolean visit(SQLIdentifierExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }

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

@@ -558,12 +558,6 @@ public class MySqlExprParser extends SQLExprParser {
             throw new ParserException("syntax error " + lexer.token() + " " + lexer.stringVal());
         }
 
-        if (lexer.token() == Token.COMMENT) {
-            lexer.nextToken();
-            column.setComment(lexer.stringVal());
-            accept(Token.LITERAL_CHARS);
-        }
-
         if (identifierEquals("STORAGE")) {
             lexer.nextToken();
             SQLExpr expr = expr();
@@ -727,7 +721,7 @@ public class MySqlExprParser extends SQLExprParser {
         if (lexer.token() == Token.KEY) {
             lexer.nextToken();
         }
-        
+
         if (lexer.token() == Token.INDEX) {
             lexer.nextToken();
         }

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

@@ -24,6 +24,7 @@ import com.alibaba.druid.sql.ast.expr.SQLBetweenExpr;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCaseExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
+import com.alibaba.druid.sql.ast.expr.SQLHexExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLInListExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
@@ -33,6 +34,7 @@ import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
 import com.alibaba.druid.sql.ast.expr.SQLQueryExpr;
 import com.alibaba.druid.sql.ast.expr.SQLUnaryExpr;
 import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
+import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBooleanExpr;
 import com.alibaba.druid.sql.visitor.SQLEvalVisitor;
 import com.alibaba.druid.sql.visitor.SQLEvalVisitorUtils;
@@ -94,6 +96,14 @@ public class MySqlEvalVisitorImpl extends MySqlASTVisitorAdapter implements SQLE
     public boolean visit(SQLNumberExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }
+    
+    public boolean visit(SQLHexExpr x) {
+        return SQLEvalVisitorUtils.visit(this, x);
+    }
+    
+    public boolean visit(MySqlBinaryExpr x) {
+        return SQLEvalVisitorUtils.visit(this, x);
+    }
 
     @Override
     public boolean visit(SQLCaseExpr x) {

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

@@ -324,6 +324,11 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
             print(' ');
             item.accept(this);
         }
+        
+        if (x.getComment() != null) {
+            print(" COMMENT ");
+            x.getComment().accept(this);
+        }
 
         return false;
     }

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

@@ -135,7 +135,7 @@ public class OracleEvalVisitor extends OracleASTVisitorAdapter implements SQLEva
     public void registerFunction(String funcName, Function function) {
         functions.put(funcName, function);
     }
-    
+
     public boolean visit(SQLIdentifierExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/visitor/PGEvalVisitor.java

@@ -135,7 +135,7 @@ public class PGEvalVisitor extends PGASTVisitorAdapter implements SQLEvalVisitor
     public void registerFunction(String funcName, Function function) {
         functions.put(funcName, function);
     }
-    
+
     public boolean visit(SQLIdentifierExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/visitor/SQLServerEvalVisitor.java

@@ -92,7 +92,7 @@ public class SQLServerEvalVisitor extends SQLServerASTVisitorAdapter implements
     public boolean visit(SQLNumberExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }
-
+    
     @Override
     public boolean visit(SQLCaseExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);

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

@@ -1478,7 +1478,7 @@ public class SQLExprParser extends SQLParser {
                 column.getConstaints().add(check);
                 return parseColumnRest(column);
             }
-            
+
             if (lexer.token == Token.DEFAULT) {
                 lexer.nextToken();
                 SQLExpr expr = this.expr();
@@ -1494,6 +1494,11 @@ public class SQLExprParser extends SQLParser {
             column.getConstaints().add(check);
             return parseColumnRest(column);
         }
+        
+        if (lexer.token() == Token.COMMENT) {
+            lexer.nextToken();
+            column.setComment(primary());
+        }
 
         return column;
     }

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

@@ -23,6 +23,7 @@ import java.util.Map;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCaseExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
+import com.alibaba.druid.sql.ast.expr.SQLHexExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLInListExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
@@ -86,6 +87,10 @@ public class SQLEvalVisitorImpl extends SQLASTVisitorAdapter implements SQLEvalV
     public boolean visit(SQLNumberExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }
+    
+    public boolean visit(SQLHexExpr x) {
+        return SQLEvalVisitorUtils.visit(this, x);
+    }
 
     @Override
     public boolean visit(SQLCaseExpr x) {

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

@@ -15,6 +15,7 @@
  */
 package com.alibaba.druid.sql.visitor;
 
+import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_ERROR;
 import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_EXPR;
 import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_VALUE;
 import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_VALUE_NULL;
@@ -40,6 +41,7 @@ import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOperator;
 import com.alibaba.druid.sql.ast.expr.SQLCaseExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
+import com.alibaba.druid.sql.ast.expr.SQLHexExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLInListExpr;
 import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
@@ -53,6 +55,7 @@ import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLSelectItem;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.db2.visitor.DB2EvalVisitor;
+import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlEvalVisitorImpl;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleEvalVisitor;
 import com.alibaba.druid.sql.dialect.postgresql.visitor.PGEvalVisitor;
@@ -84,6 +87,7 @@ import com.alibaba.druid.sql.visitor.functions.Substring;
 import com.alibaba.druid.sql.visitor.functions.Trim;
 import com.alibaba.druid.sql.visitor.functions.Ucase;
 import com.alibaba.druid.sql.visitor.functions.Unhex;
+import com.alibaba.druid.util.HexBin;
 import com.alibaba.druid.util.JdbcUtils;
 import com.alibaba.druid.wall.spi.WallVisitorUtils;
 import com.alibaba.druid.wall.spi.WallVisitorUtils.WallConditionContext;
@@ -192,6 +196,7 @@ public class SQLEvalVisitorUtils {
         functions.put("lpad", Lpad.instance);
         functions.put("ltrim", Ltrim.instance);
         functions.put("mid", Substring.instance);
+        functions.put("substr", Substring.instance);
         functions.put("substring", Substring.instance);
         functions.put("right", Right.instance);
         functions.put("reverse", Reverse.instance);
@@ -554,6 +559,19 @@ public class SQLEvalVisitorUtils {
         return true;
     }
 
+    public static boolean visit(SQLEvalVisitor visitor, SQLHexExpr x) {
+        String hex = x.getHex();
+        byte[] bytes = HexBin.decode(hex);
+        String val = new String(bytes);
+        x.putAttribute(EVAL_VALUE, val);
+        return true;
+    }
+
+    public static boolean visit(SQLEvalVisitor visitor, MySqlBinaryExpr x) {
+
+        return true;
+    }
+
     public static boolean visit(SQLEvalVisitor visitor, SQLBetweenExpr x) {
         x.getTestExpr().accept(visitor);
 
@@ -715,6 +733,36 @@ public class SQLEvalVisitorUtils {
             wallConditionContext.setBitwise(true);
         }
 
+        x.getExpr().accept(visitor);
+
+        Object val = x.getExpr().getAttribute(EVAL_VALUE);
+        if (val == EVAL_ERROR) {
+            x.putAttribute(EVAL_VALUE, EVAL_ERROR);
+            return false;
+        }
+
+        switch (x.getOperator()) {
+            case BINARY:
+            case RAW:
+                x.putAttribute(EVAL_VALUE, val);
+                break;
+            case NOT:
+            case Not:
+                x.putAttribute(EVAL_VALUE, !castToBoolean(val));
+                break;
+            case Plus:
+                x.putAttribute(EVAL_VALUE, val);
+                break;
+            case Negative:
+                x.putAttribute(EVAL_VALUE, multi(val, -1));
+                break;
+            case Compl:
+                x.putAttribute(EVAL_VALUE, ~castToInteger(val));
+                break;
+            default:
+                break;
+        }
+
         return false;
     }
 
@@ -834,6 +882,18 @@ public class SQLEvalVisitorUtils {
                 value = div(leftValue, rightValue);
                 x.putAttribute(EVAL_VALUE, value);
                 break;
+            case RightShift:
+                value = rightShift(leftValue, rightValue);
+                x.putAttribute(EVAL_VALUE, value);
+                break;
+            case BitwiseAnd:
+                value = bitAnd(leftValue, rightValue);
+                x.putAttribute(EVAL_VALUE, value);
+                break;
+            case BitwiseOr:
+                value = bitOr(leftValue, rightValue);
+                x.putAttribute(EVAL_VALUE, value);
+                break;
             case GreaterThan:
                 value = gt(leftValue, rightValue);
                 x.putAttribute(EVAL_VALUE, value);
@@ -978,7 +1038,17 @@ public class SQLEvalVisitorUtils {
         }
 
         if (val instanceof Number) {
-            return ((Number) val).intValue() == 1;
+            return ((Number) val).intValue() > 0;
+        }
+
+        if (val instanceof String) {
+            if ("1".equals(val) || "true".equalsIgnoreCase((String) val)) {
+                return true;
+            }
+
+            if ("0".equals(val) || "false".equalsIgnoreCase((String) val)) {
+                return false;
+            }
         }
 
         throw new IllegalArgumentException(val.getClass() + " not supported.");
@@ -1186,6 +1256,42 @@ public class SQLEvalVisitorUtils {
         return BigDecimal.valueOf(((Number) val).longValue());
     }
 
+    public static Object rightShift(Object a, Object b) {
+        if (a == null || b == null) {
+            return null;
+        }
+
+        if (a instanceof Long || b instanceof Long) {
+            return castToLong(a).longValue() >> castToLong(b).longValue();
+        }
+
+        return castToInteger(a).intValue() >> castToInteger(b).intValue();
+    }
+
+    public static Object bitAnd(Object a, Object b) {
+        if (a == null || b == null) {
+            return null;
+        }
+
+        if (a instanceof Long || b instanceof Long) {
+            return castToLong(a).longValue() & castToLong(b).longValue();
+        }
+
+        return castToInteger(a).intValue() & castToInteger(b).intValue();
+    }
+
+    public static Object bitOr(Object a, Object b) {
+        if (a == null || b == null) {
+            return null;
+        }
+
+        if (a instanceof Long || b instanceof Long) {
+            return castToLong(a).longValue() | castToLong(b).longValue();
+        }
+
+        return castToInteger(a).intValue() | castToInteger(b).intValue();
+    }
+
     public static Object div(Object a, Object b) {
         if (a == null || b == null) {
             return null;

src/main/java/com/alibaba/druid/sql/visitor/functions/Ascii.java

@@ -16,6 +16,7 @@
 package com.alibaba.druid.sql.visitor.functions;
 
 import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_VALUE;
+import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_VALUE_NULL;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
@@ -31,15 +32,19 @@ public class Ascii implements Function {
         }
         SQLExpr param = x.getParameters().get(0);
         param.accept(visitor);
-
+        
         Object paramValue = param.getAttributes().get(EVAL_VALUE);
         if (paramValue == null) {
             return SQLEvalVisitor.EVAL_ERROR;
         }
+        
+        if (paramValue == EVAL_VALUE_NULL) {
+            return EVAL_VALUE_NULL;
+        }
 
         String strValue = paramValue.toString();
         if (strValue.length() == 0) {
-            return SQLEvalVisitor.EVAL_ERROR;
+            return 0;
         }
 
         int ascii = strValue.charAt(0);

src/main/java/com/alibaba/druid/wall/WallVisitor.java

@@ -37,4 +37,6 @@ public interface WallVisitor extends SQLASTVisitor {
     boolean isSqlModified();
 
     void setSqlModified(boolean sqlModified);
+    
+    String getDbType();
 }

src/main/java/com/alibaba/druid/wall/spi/DB2WallVisitor.java

@@ -43,6 +43,7 @@ import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
 import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock;
 import com.alibaba.druid.sql.dialect.db2.visitor.DB2ASTVisitorAdapter;
+import com.alibaba.druid.util.JdbcConstants;
 import com.alibaba.druid.wall.Violation;
 import com.alibaba.druid.wall.WallConfig;
 import com.alibaba.druid.wall.WallProvider;
@@ -62,6 +63,11 @@ public class DB2WallVisitor extends DB2ASTVisitorAdapter implements WallVisitor
         this.provider = provider;
     }
 
+    @Override
+    public String getDbType() {
+        return JdbcConstants.DB2;
+    }
+
     @Override
     public boolean isSqlModified() {
         return sqlModified;

src/main/java/com/alibaba/druid/wall/spi/MySqlWallVisitor.java

@@ -57,6 +57,7 @@ import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUnionQuery;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlUpdateStatement;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitorAdapter;
+import com.alibaba.druid.util.JdbcConstants;
 import com.alibaba.druid.wall.Violation;
 import com.alibaba.druid.wall.WallConfig;
 import com.alibaba.druid.wall.WallContext;
@@ -77,6 +78,11 @@ public class MySqlWallVisitor extends MySqlASTVisitorAdapter implements WallVisi
         this.config = provider.getConfig();
         this.provider = provider;
     }
+    
+    @Override
+    public String getDbType() {
+        return JdbcConstants.MYSQL;
+    }
 
     @Override
     public boolean isSqlModified() {

src/main/java/com/alibaba/druid/wall/spi/OracleWallVisitor.java

@@ -51,6 +51,7 @@ import com.alibaba.druid.sql.dialect.oracle.ast.stmt.OracleSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.oracle.ast.stmt.OracleSelectTableReference;
 import com.alibaba.druid.sql.dialect.oracle.ast.stmt.OracleUpdateStatement;
 import com.alibaba.druid.sql.dialect.oracle.visitor.OracleASTVisitorAdapter;
+import com.alibaba.druid.util.JdbcConstants;
 import com.alibaba.druid.wall.Violation;
 import com.alibaba.druid.wall.WallConfig;
 import com.alibaba.druid.wall.WallProvider;
@@ -69,6 +70,11 @@ public class OracleWallVisitor extends OracleASTVisitorAdapter implements WallVi
         this.config = provider.getConfig();
         this.provider = provider;
     }
+    
+    @Override
+    public String getDbType() {
+        return JdbcConstants.ORACLE;
+    }
 
     @Override
     public boolean isSqlModified() {

src/main/java/com/alibaba/druid/wall/spi/PGWallVisitor.java

@@ -43,6 +43,7 @@ import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
 import com.alibaba.druid.sql.dialect.postgresql.ast.stmt.PGSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.postgresql.visitor.PGASTVisitorAdapter;
+import com.alibaba.druid.util.JdbcConstants;
 import com.alibaba.druid.wall.Violation;
 import com.alibaba.druid.wall.WallConfig;
 import com.alibaba.druid.wall.WallProvider;
@@ -61,6 +62,11 @@ public class PGWallVisitor extends PGASTVisitorAdapter implements WallVisitor {
         this.config = provider.getConfig();
         this.provider = provider;
     }
+    
+    @Override
+    public String getDbType() {
+        return JdbcConstants.POSTGRESQL;
+    }
 
     @Override
     public boolean isSqlModified() {

src/main/java/com/alibaba/druid/wall/spi/SQLServerWallVisitor.java

@@ -47,6 +47,7 @@ import com.alibaba.druid.sql.dialect.sqlserver.ast.expr.SQLServerObjectReference
 import com.alibaba.druid.sql.dialect.sqlserver.ast.stmt.SQLServerInsertStatement;
 import com.alibaba.druid.sql.dialect.sqlserver.visitor.SQLServerASTVisitor;
 import com.alibaba.druid.sql.dialect.sqlserver.visitor.SQLServerASTVisitorAdapter;
+import com.alibaba.druid.util.JdbcConstants;
 import com.alibaba.druid.wall.Violation;
 import com.alibaba.druid.wall.WallConfig;
 import com.alibaba.druid.wall.WallProvider;
@@ -65,6 +66,11 @@ public class SQLServerWallVisitor extends SQLServerASTVisitorAdapter implements
         this.config = provider.getConfig();
         this.provider = provider;
     }
+    
+    @Override
+    public String getDbType() {
+        return JdbcConstants.SQL_SERVER;
+    }
 
     @Override
     public boolean isSqlModified() {

src/main/java/com/alibaba/druid/wall/spi/WallVisitorUtils.java

@@ -47,6 +47,7 @@ import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
 import com.alibaba.druid.sql.ast.expr.SQLNumericLiteralExpr;
 import com.alibaba.druid.sql.ast.expr.SQLPropertyExpr;
 import com.alibaba.druid.sql.ast.expr.SQLQueryExpr;
+import com.alibaba.druid.sql.ast.expr.SQLUnaryExpr;
 import com.alibaba.druid.sql.ast.statement.SQLAlterTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLCallStatement;
 import com.alibaba.druid.sql.ast.statement.SQLCreateIndexStatement;
@@ -612,8 +613,10 @@ public class WallVisitorUtils {
 
             boolean allFalse = true;
             for (int i = groupList.size() - 1; i >= 0; --i) {
-                Object result = getValue(visitor, groupList.get(i));
-                if (Boolean.TRUE == result) {
+                SQLExpr item = groupList.get(i);
+                Object result = getValue(visitor, item);
+                Boolean booleanVal = SQLEvalVisitorUtils.castToBoolean(result);
+                if (Boolean.TRUE == booleanVal) {
                     final WallConditionContext wallContext = WallVisitorUtils.getWallConditionContext();
                     if (wallContext != null && i != 0) {
                         wallContext.setPartAlwayTrue(true);
@@ -621,7 +624,7 @@ public class WallVisitorUtils {
                     return true;
                 }
 
-                if (Boolean.FALSE != result) {
+                if (Boolean.FALSE != booleanVal) {
                     allFalse = false;
                 }
             }
@@ -973,63 +976,14 @@ public class WallVisitorUtils {
             }
         }
 
-        if (x instanceof SQLMethodInvokeExpr) {
-            return getValue(visitor, (SQLMethodInvokeExpr) x);
+        if (x instanceof SQLMethodInvokeExpr || x instanceof SQLUnaryExpr) {
+            String dbType = null;
+            if (visitor != null) {
+                dbType = visitor.getDbType();
+            }
+            return SQLEvalVisitorUtils.eval(dbType, x, Collections.emptyList(), false);
         }
-
-        return null;
-    }
-
-    public static Object getValue(WallVisitor visitor, SQLMethodInvokeExpr x) {
-        String methodName = x.getMethodName();
-        if ("len".equalsIgnoreCase(methodName) || "length".equalsIgnoreCase(methodName)) {
-            Object firstValue = null;
-            if (x.getParameters().size() > 0) {
-                firstValue = (getValue(visitor, x.getParameters().get(0)));
-            }
-
-            if (firstValue instanceof String) {
-                return ((String) firstValue).length();
-            }
-        }
-
-        if ("if".equalsIgnoreCase(methodName) && x.getParameters().size() == 3) {
-            SQLExpr first = x.getParameters().get(0);
-            Object firstResult = getValue(visitor, first);
-
-            if (Boolean.TRUE == firstResult) {
-                return getValue(visitor, x.getParameters().get(1));
-            }
-
-            if (Boolean.FALSE == firstResult) {
-                getValue(visitor, x.getParameters().get(2));
-            }
-        }
-
-        if ("chr".equalsIgnoreCase(methodName) && x.getParameters().size() == 1) {
-            SQLExpr first = x.getParameters().get(0);
-            Object firstResult = getValue(visitor, first);
-            if (firstResult instanceof Number) {
-                int intValue = ((Number) firstResult).intValue();
-                char ch = (char) intValue;
-
-                return "" + ch;
-            }
-        }
-
-        if ("concat".equalsIgnoreCase(methodName)) {
-            StringBuffer buf = new StringBuffer();
-            for (SQLExpr expr : x.getParameters()) {
-                Object value = getValue(visitor, expr);
-                if (value == null) {
-                    return null;
-                }
-
-                buf.append(value.toString());
-            }
-            return buf.toString();
-        }
-
+        
         return null;
     }