Expression item
In Filters, an 
Unlike Relation items, expression items never add rows or columns to the output table. Expression items are not join operations. They can only produce an output with the same or fewer number of rows, and the same columns.
Tip
Logical operators in expression items cannot reference data in other tables. However, Lookups are a potential workaround. They are akin to expression items with an "exists in target column" logical operator.
Expression items can take constant values or Parameters.
The following logical operators are available:
- Contains (ci)
Case-insensitive whole string or substring match.
- Not Contains (ci)
Inverts the results of Contains (ci).
- Equals (ci)
Case-insensitive whole string match.
- Not Equals (ci)
Inverts the results of Equals (ci).
- Equals
Case-sensitive whole string match.
- Not Equals
Inverts the results of Equals.
- Exists
Includes all rows that have non-empty values for this column.
- Not Exists
Inverts the results of Exists.
- In
Comma separated list of multiple string values required for record(s) to return.
- Not In
Inverse of In. Comma separated list of string that if they are found the record is not returned.
- Regex
Regex pattern match. Supports flags. For example:
/[ab]/i- Matches
Similar to Regex, but does not support flags. For example:
[ab]- Not Matches
Inverse of matches. Similar to Regex, but does not support flags. For example:
[ab]- Starts-With (ci)
Similar to Contains (ci), but only match starting at position 0.
- Not Starts-With (ci)
Similar to Contains (ci), but only match starting at position 0. Case insensitive
- Starts-With (cs)
Similar to Starts-With (ci), but case sensitive.
- Not starts with (cs)
Inverse of Starts with (cs). Similar to Contains (ci), but only match starting at position 0. Case sensitive.