6  Column Value Validations

6.1 Comparison validations

6.1.1 Inclusive versus strict bounds

6.1.2 Equality and inequality

6.1.3 Comparing against another column

6.1.4 Handling nulls in comparisons

6.2 Range validations

6.2.1 Between

6.2.2 Outside

6.3 Set membership validations

6.3.1 In set

6.3.2 Not in set

6.4 Null validations

6.4.1 Requiring values to be absent

6.5 Pattern matching

6.6 Validating against known formats

6.7 Sequence validations

6.7.1 Increasing and decreasing values

6.8 Selecting columns

6.8.1 Explicit lists and selector functions

6.9 Tagging checks with a quality dimension

6.10 Beyond single-column checks