#### 15.7.5.2 Implicit Categories ¶

In the absence of an explicit list of categories, `CATEGORIES` allows `KEY`, `ORDER`, and `MISSING` to specify how to select and sort categories.

The `KEY` setting specifies the sort key. By default, or with `KEY=VALUE`, categories are sorted by default. Categories may also be sorted by value label, with `KEY=LABEL`, or by the value of a summary function, e.g. `KEY=COUNT`.

By default, or with `ORDER=A`, categories are sorted in ascending order. Specify `ORDER=D` to sort in descending order.

User-missing values are excluded by default, or with `MISSING=EXCLUDE`. Specify `MISSING=INCLUDE` to include user-missing values. The system-missing value is always excluded.

The following example syntax and output show how `MISSING=INCLUDE` causes missing values to be included in a category list.

    CTABLES /TABLE freqOfDriving.
    CTABLES /TABLE freqOfDriving
            /CATEGORIES VARIABLES=freqOfDriving MISSING=INCLUDE.

Custom Tables
|  | Count
--- | --- | ---
1. How often do you usually drive a car or other motor vehicle? | Every day | 4667
Several days a week | 1274
Once a week or less | 361
Only certain times a year | 130
Never | 540

Custom Tables
|  | Count
--- | --- | ---
1. How often do you usually drive a car or other motor vehicle? | Every day | 4667
Several days a week | 1274
Once a week or less | 361
Only certain times a year | 130
Never | 540
Don't know | 8
Refused | 19