fix not support ALTER TABLE XXX ADD KEY xxx('xxx')

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

@@ -20,6 +20,7 @@ import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.SQLObjectImpl;
+import com.alibaba.druid.sql.parser.Token;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class SQLAlterTableAddIndex extends SQLObjectImpl implements SQLAlterTableItem {
@@ -33,6 +34,8 @@ public class SQLAlterTableAddIndex extends SQLObjectImpl implements SQLAlterTabl
     private String                           type;
 
     private String                           using;
+    
+    private String                           keyOrIndex = Token.INDEX.name;
 
     @Override
     protected void accept0(SQLASTVisitor visitor) {
@@ -79,4 +82,11 @@ public class SQLAlterTableAddIndex extends SQLObjectImpl implements SQLAlterTabl
         this.using = using;
     }
 
+    public String getKeyOrIndex() {
+        return keyOrIndex;
+    }
+
+    public void setKeyOrIndex(String keyOrIndex) {
+        this.keyOrIndex = keyOrIndex;
+    }
 }

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

@@ -2290,7 +2290,11 @@ public class MySqlStatementParser extends SQLStatementParser {
                         SQLAlterTableAddConstraint item = new SQLAlterTableAddConstraint(primaryKey);
                         stmt.getItems().add(item);
                     } else if (lexer.token() == Token.KEY) {
-                        throw new ParserException("TODO " + lexer.token() + " " + lexer.stringVal());
+                        // throw new ParserException("TODO " + lexer.token() +
+                        // " " + lexer.stringVal());
+                        SQLAlterTableAddIndex item = parseAlterTableAddIndex();
+                        item.setParent(stmt);
+                        stmt.getItems().add(item);
                     } else if (lexer.token() == Token.CONSTRAINT) {
                         lexer.nextToken();
                         SQLName constraintName = this.exprParser.name();

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

@@ -1688,10 +1688,20 @@ public class SQLStatementParser extends SQLParser {
             item.setUnique(true);
             lexer.nextToken();
             if (lexer.token() == Token.INDEX) {
+                item.setKeyOrIndex(Token.INDEX.name);
+                lexer.nextToken();
+            } else if (lexer.token() == Token.KEY) {
+                item.setKeyOrIndex(Token.KEY.name);
                 lexer.nextToken();
             }
         } else {
-            accept(Token.INDEX);
+            if (lexer.token() == Token.INDEX) {
+                item.setKeyOrIndex(Token.INDEX.name);
+                accept(Token.INDEX);
+            } else if (lexer.token() == Token.KEY) {
+                item.setKeyOrIndex(Token.KEY.name);
+                accept(Token.KEY);
+            }
         }
 
         if (lexer.token() == Token.LPAREN) {

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

@@ -1990,7 +1990,8 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Printab
             print("UNIQUE ");
         }
 
-        print("INDEX ");
+        print(x.getKeyOrIndex());
+        print(" ");
 
         if (x.getName() != null) {
             x.getName().accept(this);