improved sql parser.

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

@@ -15,6 +15,11 @@
  */
 package com.alibaba.druid.sql.parser;
 
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.util.JdbcUtils;
+import com.alibaba.druid.util.Utils;
+
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -25,6 +30,9 @@ public class Keywords {
 
     private final Map<String, Token> keywords;
 
+    private long[] hashArray;
+    private Token[] tokens;
+
     public final static Keywords     DEFAULT_KEYWORDS;
 
     public final static Keywords     SQLITE_KEYWORDS;
@@ -169,11 +177,38 @@ public class Keywords {
 
     public Keywords(Map<String, Token> keywords){
         this.keywords = keywords;
+
+        this.hashArray = new long[keywords.size()];
+        this.tokens = new Token[keywords.size()];
+
+        int index = 0;
+        for (String k : keywords.keySet()) {
+            hashArray[index++] = Utils.fnv_64_lower(k);
+        }
+        Arrays.sort(hashArray);
+        for (Map.Entry<String, Token> entry : keywords.entrySet()) {
+            long k = Utils.fnv_64_lower(entry.getKey());
+            index = Arrays.binarySearch(hashArray, k);
+            tokens[index] = entry.getValue();
+        }
+    }
+
+    public Token getKeyword(long hash) {
+        int index = Arrays.binarySearch(hashArray, hash);
+        if (index < 0) {
+            return null;
+        }
+        return tokens[index];
     }
 
     public Token getKeyword(String key) {
-        key = key.toUpperCase();
-        return keywords.get(key);
+        long k = Utils.fnv_64_lower(key);
+        int index = Arrays.binarySearch(hashArray, k);
+        if (index < 0) {
+            return null;
+        }
+        return tokens[index];
+//        return keywords.get(key);
     }
 
     public Map<String, Token> getKeywords() {

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

@@ -1417,6 +1417,9 @@ public class Lexer {
      * The value of a literal token, recorded as a string. For integers, leading 0x and 'l' suffixes are suppressed.
      */
     public final String stringVal() {
+        if (stringVal == null) {
+            stringVal = subString(mark, bufPos);
+        }
         return stringVal;
     }
     

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

@@ -659,7 +659,7 @@ public class SQLExprParser extends SQLParser {
                 break;
             }
             default:
-                throw new ParserException("ERROR" + lexer.info());
+                throw new ParserException("ERROR. " + lexer.info());
         }
 
         SQLExpr expr = primaryRest(sqlExpr);
@@ -882,6 +882,12 @@ public class SQLExprParser extends SQLParser {
                 methodInvokeExpr.setFrom(from);
             }
 
+            if (lexer.token == Token.USING) {
+                lexer.nextToken();
+                SQLExpr using = this.primary();
+                methodInvokeExpr.setUsing(using);
+            }
+
             accept(Token.RPAREN);
 
             if (lexer.token() == Token.OVER) {