text: -- join4.test
  -- 
  -- execsql {
  --       create table t1(a integer, b varchar(10));
  --       insert into t1 values(1,'one');
  --       insert into t1 values(2,'two');
  --       insert into t1 values(3,'three');
  --       insert into t1 values(4,'four');
  --   
  --       create table t2(x integer, y varchar(10), z varchar(10));
  --       insert into t2 values(2,'niban','ok');
  --       insert into t2 values(4,'yonban','err');
  -- }
  create table t1(a integer, b varchar(10));
  insert into t1 values(1,'one');
  insert into t1 values(2,'two');
  insert into t1 values(3,'three');
  insert into t1 values(4,'four');
  create table t2(x integer, y varchar(10), z varchar(10));
  insert into t2 values(2,'niban','ok');
  insert into t2 values(4,'yonban','err');