@pmbohm liquibase has in built support for adding columns, so these changes could be written like:

```groovy
changeSet(author: "pmbohm (generated)", id: "20131111-PB-extra-filter-parameters") {
    addColumn(tableName: "filter") {
        column(name: "wms_start_date_name", type: "character varying(255)")
    }
    addColumn(tableName: "filter") {
        column(name: "wms_end_date_name", type: "character varying(255)")
    }
}

```