This feature got into 6.6 with lvm2 v2.02.107. I'm cloning this feature bug for 6.6 and QA to test this/comment on this.

+++ This bug was initially created as a clone of Bug #867376 +++
--- Additional comment from Peter Rajnoha on 2014-06-24 09:15:14 CEST ---

The final released version looks like this (lvm2 v2.02.107/libdevmapper v1.02.86):

pvs/vgs/lvs/pvdisplay/vgdisplay/lvdisplay/lvm devtypes -S SELECTION

# pvs -S help

  Selection operands
  ------------------
    field               - Reporting field.
    number              - Non-negative integer value.
    size                - Floating point value with units, 'm' unit used by default if not specified.
    percent             - Non-negative integer with or without % suffix.
    string              - Characters quoted by ' or " or unquoted.
    string list         - Strings enclosed by [ ] and elements delimited by either
                          "all items must match" or "at least one item must match" operator.
    regular expression  - Characters quoted by ' or " or unquoted.
   
  Reserved values
  ---------------
    -1, undefined, undef, unknown   - Reserved value for undefined numeric value. [number]
    unmanaged                       - Reserved value for unmanaged number of metadata copies in VG. [number]
    auto                            - Reserved value for size that is automatically calculated. [size]
   
  Selection operators
  -------------------
    Comparison operators:
        =~  - Matching regular expression. [regex]
        !~  - Not matching regular expression. [regex]
         =  - Equal to. [number, size, percent, string, string list]
        !=  - Not equal to. [number, size, percent, string, string_list]
        >=  - Greater than or equal to. [number, size, percent]
         >  - Greater than. [number, size, percent]
        <=  - Less than or equal to. [number, size, percent]
         <  - Less than. [number, size, percent]
   
    Logical and grouping operators:
        &&  - All fields must match
         ,  - All fields must match
        ||  - At least one field must match
         #  - At least one field must match
         !  - Logical negation
         (  - Left parenthesis
         )  - Right parenthesis
         [  - List start
         ]  - List end


(the reserved values are specific to the tool, e.g. dmsetup doesn't define any of these reserved values)

From man lvm (8):

Informal grammar specification:

              STATEMENT = column cmp_op VALUE | STATEMENT log_op STATEMENT | (STATEMENT) | !(STATEMENT)

              VALUE = [VALUE log_op VALUE]
              For list-based types: string list. The log_op must always be of one type within the whole list value.

              VALUE = value
              For scalar types: number (integer), size (floating point number with size unit suffix), percent (floating point number with or without % suffix), string.