With

Keyword WITH

In AlaSQL you can use WITH caluse with SELECT operator to create temporary tables for current select (a.k.a. Commom Table Expressions).

A common table expression (CTE) can be thought of as a temporary result set that is defined within the execution scope of a single SELECT, INSERT, UPDATE, DELETE, or CREATE VIEW statement. A CTE is similar to a derived table in that it is not stored as an object and lasts only for the duration of the query. CTE can be referenced multiple times in the same query.

Source

In current version of AlaSQL CTE canot be self-referencing.

 With Totals as
 (
    select  *,
            price * quantity as [Total price]
    from    grocery
 )
 select  *
    ,  case
         when [Total price]>100 and [Total price]<= 200 then '2%'
         when [Total price]>200 and [Total price]<= 300 then '3%'
         when [Total price]>300 and [Total price]<= 400 then '4%'
        else '0%'
     end as tax
 
 from
   Totals

You can try this example in jsFiddle.

    var res = alasql('WITH one AS (SELECT * FROM ?),\
                           two AS (SELECT * FROM ?)\
                      SELECT * FROM one,two', [[{a:1},{a:2}],[{b:10},{b:20}]]);

You can try this example in jsFiddle.