To whomever likes SQL:

Using the SequelSphereDB engine, I was able to create an 'Ext.ux.data.SqlStore' Class that allows you to execute SQL against any data Store(s) managed by Ext.data.StoreManager. Here is some sample usage code:

Code:
var store = Ext.create('Ext.ux.data.SqlStore', {
    storeId: "EmplDeptQuery",
    sql: "SELECT empl_id, e.name, age, d.name as dept_name " +
         "  FROM empl e " +
         "  JOIN dept d " +
         "    ON e.dept_id = d.dept_id " +
         " WHERE age > 20"
});
In the above example, 'Empl' is an Ext.data.ArrayStore, and 'Dept' is an Ext.data.JsonStore.

When SQL is executed, it all occurs in the browser, using the SequelSphereDB engine to parse and execute the SQL.

The Code for Ext.ux.data.SqlStore can be found here:
And an example app showing integration with a Grid and Chart along with more sample code can be found here:
As one last example, consider this: let's get the departments whose managers are younger than the average age of the employees in the department.

Code:
var store = Ext.create('Ext.ux.data.SqlStore', {
    storeId: "EmplDeptQuery",
    sql: "SELECT d.name, count(*) as nbr_empls, avg(e.age) as age " +
         "     , m.name as mgr_name, m.age as mgr_age " +
         "  FROM dept d " +
         "  JOIN empl e ON e.dept_id = d.dept_id " +
         "  JOIN empl m ON m.empl_id = d.mgr_id " +
         " GROUP BY d.name, m.name, m.age " +
         "HAVING m.age <= avg(e.age) " +
         " ORDER BY avg(e.age) - m.age desc"
});
All feedback is welcome. Please let me know if there are other ways you think SQL could be incorporated with ExtJS.

Cheers!

john...