1.7.38 CQL: ON

CQL supports both constant and shared variable join specifications. This is particularly useful when specifying outer joins.

Example

{[],
 se_lt_x :: [a-UserNameA,
             b-RealName,
             d-FavouriteColour]
 *==
 se_lt_x :: [a-UserNameB,
             e-FavouriteFood] on( UserNameA == UserNameB,
                                  FavouriteColour == FavouriteFood,
                                  FavouriteFood == 'ORANGE')}

All the CQL comparison operators, <, =<, ==, =~, \=~, \==, >=, > can be used in ON specifications.

For example:

{[],
 se_lt_z :: [i-J1, k-K]
 *==
 se_lt_x :: [c-J1, a-A, b-B] on A \== 'A1'},