diff --git a/src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlExprParser.java b/src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlExprParser.java
index 3be6b62fef..deef36e75f 100644
--- a/src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlExprParser.java
+++ b/src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlExprParser.java
@@ -22,7 +22,6 @@ import com.alibaba.druid.sql.ast.SQLOrderBy;
 import com.alibaba.druid.sql.ast.expr.SQLAggregateExpr;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOperator;
-import com.alibaba.druid.sql.ast.expr.SQLBooleanExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
 import com.alibaba.druid.sql.ast.expr.SQLHexExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
@@ -484,6 +483,11 @@ public class MySqlExprParser extends SQLExprParser {
             lexer.nextToken();
             return userName;
         }
+        
+        if(lexer.token() == Token.ERROR) {
+            throw new ParserException("syntax error, token: " + lexer.token() + " " + lexer.stringVal() + ", pos : "
+                                      + lexer.pos());
+        }
 
         return super.primaryRest(expr);
     }
diff --git a/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java b/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java
index 18003fd8a9..7564d5f2c2 100644
--- a/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java
+++ b/src/main/java/com/alibaba/druid/sql/visitor/SQLEvalVisitorUtils.java
@@ -1239,6 +1239,14 @@ public class SQLEvalVisitorUtils {
                 return castToLong(list.get(0));
             }
         }
+        
+        if (val instanceof Boolean) {
+            if (((Boolean) val).booleanValue()) {
+                return 1l;
+            } else {
+                return 0l;
+            }
+        }
 
         return ((Number) val).longValue();
     }
@@ -1322,8 +1330,12 @@ public class SQLEvalVisitorUtils {
             return new BigInteger(val);
         } catch (NumberFormatException e) {
         }
-
-        return new BigDecimal(val);
+        
+        try {
+            return new BigDecimal(val);
+        } catch (NumberFormatException e) {
+            return 0;
+        }
     }
 
     public static Date castToDate(Object val) {
@@ -1406,6 +1418,18 @@ public class SQLEvalVisitorUtils {
         if (a == null || b == null) {
             return null;
         }
+        
+        if(a == EVAL_VALUE_NULL || b == EVAL_VALUE_NULL) {
+            return null;
+        }
+        
+        if (a instanceof String) {
+            a = castToNumber((String) a);
+        }
+
+        if (b instanceof String) {
+            b = castToNumber((String) b);
+        }
 
         if (a instanceof Long || b instanceof Long) {
             return castToLong(a).longValue() & castToLong(b).longValue();
@@ -1418,6 +1442,18 @@ public class SQLEvalVisitorUtils {
         if (a == null || b == null) {
             return null;
         }
+        
+        if(a == EVAL_VALUE_NULL || b == EVAL_VALUE_NULL) {
+            return null;
+        }
+        
+        if (a instanceof String) {
+            a = castToNumber((String) a);
+        }
+
+        if (b instanceof String) {
+            b = castToNumber((String) b);
+        }
 
         if (a instanceof Long || b instanceof Long) {
             return castToLong(a).longValue() | castToLong(b).longValue();
@@ -1431,6 +1467,10 @@ public class SQLEvalVisitorUtils {
             return null;
         }
         
+        if(a == EVAL_VALUE_NULL || b == EVAL_VALUE_NULL) {
+            return null;
+        }
+        
         if (a instanceof String) {
             a = castToNumber((String) a);
         }
@@ -1475,7 +1515,18 @@ public class SQLEvalVisitorUtils {
         }
 
         if (a instanceof Long || b instanceof Long) {
-            return castToLong(a) / castToLong(b);
+            Long longA = castToLong(a);
+            Long longB = castToLong(b);
+            if (longB == 0) {
+                if (longA > 0) {
+                    return Double.POSITIVE_INFINITY;
+                } else if (longA < 0) {
+                    return Double.NEGATIVE_INFINITY;
+                } else {
+                    return Double.NaN;
+                }
+            }
+            return longA / longB;
         }
 
         if (a instanceof Integer || b instanceof Integer) {
@@ -1648,6 +1699,10 @@ public class SQLEvalVisitorUtils {
         if (a == null || b == null) {
             return false;
         }
+        
+        if (a == EVAL_VALUE_NULL || b == EVAL_VALUE_NULL) {
+            return false;
+        }
 
         if (a.equals(b)) {
             return true;
diff --git a/src/main/java/com/alibaba/druid/sql/visitor/functions/Char.java b/src/main/java/com/alibaba/druid/sql/visitor/functions/Char.java
index 27f9146982..301fb4352d 100644
--- a/src/main/java/com/alibaba/druid/sql/visitor/functions/Char.java
+++ b/src/main/java/com/alibaba/druid/sql/visitor/functions/Char.java
@@ -42,8 +42,11 @@ public class Char implements Function {
                 int charCode = ((Number) paramValue).intValue();
                 buf.append((char) charCode);
             } else if (paramValue instanceof String) {
-                int charCode = new BigDecimal((String)paramValue).intValue();
-                buf.append((char) charCode);
+                try {
+                    int charCode = new BigDecimal((String) paramValue).intValue();
+                    buf.append((char) charCode);
+                } catch (NumberFormatException e) {
+                }
             } else {
                 return SQLEvalVisitor.EVAL_ERROR;
             }
diff --git a/src/main/java/com/alibaba/druid/sql/visitor/functions/Substring.java b/src/main/java/com/alibaba/druid/sql/visitor/functions/Substring.java
index 9e11949825..fe6ecb9914 100644
--- a/src/main/java/com/alibaba/druid/sql/visitor/functions/Substring.java
+++ b/src/main/java/com/alibaba/druid/sql/visitor/functions/Substring.java
@@ -50,7 +50,7 @@ public class Substring implements Function {
 
         if (paramSize == 2) {
 
-            if (index < 0) {
+            if (index <= 0) {
                 int lastIndex = str.length() + index;
                 return str.substring(lastIndex);
             }
@@ -68,7 +68,7 @@ public class Substring implements Function {
         int len = ((Number) param2Value).intValue();
 
         String result;
-        if (index < 0) {
+        if (index <= 0) {
             int lastIndex = str.length() + index;
             result = str.substring(lastIndex);
         } else {