improve sql parser for db2

src/main/java/com/alibaba/druid/sql/dialect/db2/ast/stmt/DB2SelectQueryBlock.java

@@ -23,7 +23,9 @@ import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class DB2SelectQueryBlock extends SQLSelectQueryBlock implements DB2Object {
 
-    private SQLExpr first;
+    private SQLExpr   first;
+
+    private Isolation isolation;
 
     public SQLExpr getFirst() {
         return first;
@@ -54,4 +56,16 @@ public class DB2SelectQueryBlock extends SQLSelectQueryBlock implements DB2Objec
         }
         visitor.endVisit(this);
     }
+
+    public Isolation getIsolation() {
+        return isolation;
+    }
+
+    public void setIsolation(Isolation isolation) {
+        this.isolation = isolation;
+    }
+
+    public static enum Isolation {
+        RR, RS, CS, UR
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2SelectParser.java

@@ -19,6 +19,8 @@ import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.SQLSetQuantifier;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
 import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock;
+import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock.Isolation;
+import com.alibaba.druid.sql.parser.ParserException;
 import com.alibaba.druid.sql.parser.SQLExprParser;
 import com.alibaba.druid.sql.parser.SQLSelectParser;
 import com.alibaba.druid.sql.parser.Token;
@@ -74,7 +76,7 @@ public class DB2SelectParser extends SQLSelectParser {
         parseWhere(queryBlock);
 
         parseGroupBy(queryBlock);
-        
+
         if (lexer.token() == Token.FETCH) {
             lexer.nextToken();
             accept(Token.FIRST);
@@ -86,6 +88,22 @@ public class DB2SelectParser extends SQLSelectParser {
             accept(Token.ONLY);
         }
 
+        if (lexer.token() == Token.WITH) {
+            lexer.nextToken();
+            if (identifierEquals("RR")) {
+                queryBlock.setIsolation(Isolation.RR);
+            } else if (identifierEquals("RS")) {
+                queryBlock.setIsolation(Isolation.RS);
+            } else if (identifierEquals("CS")) {
+                queryBlock.setIsolation(Isolation.CS);
+            } else if (identifierEquals("UR")) {
+                queryBlock.setIsolation(Isolation.UR);
+            } else {
+                throw new ParserException("TODO");
+            }
+            lexer.nextToken();
+        }
+
         return queryRest(queryBlock);
     }
 }

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2OutputVisitor.java

@@ -36,6 +36,12 @@ public class DB2OutputVisitor extends SQLASTOutputVisitor implements DB2ASTVisit
             print(" ROWS ONLY");
         }
         
+        if (x.getIsolation() != null) {
+            println();
+            print("WITH ");
+            print(x.getIsolation().name());
+        }
+        
         return false;
     }