SQLite Db Sync call back

Because its asynchronous code. You need to put your code in the block of callback if you want waiting until finish

sql = "select * from muser" ;
 db.executeSql(sql,{})
      .then((data) => {
           console.log("Got data from DB");
Http.post(url, data);  // here send your data to your server. 
       })
      .catch(e => console.log(e))