A method, apparatus, and program product are provided for creating an Encoded Matrix Index for a column in a database table. An element of the column for all rows in the database table is compared to a corresponding reference value in a reference data structure, and in response to at least one value for the element of the column not matching the reference value, indicating a variation in a variation data structure and creating a value data structure. Queries executed using the Encoded Matrix Index include terms associated with a sub-column defined in a column of a database table. The variation data structure is accessed to determine whether any variation exists between rows belonging to a sub-column of the database table. If no variation exists, a value is accessed from the reference data structure; otherwise, a value for each row of the sub-column is accessed from a value data structure.