#+TITLE: MU QUERY
#+MAN_CLASS_OPTIONS: :section-id "@SECTION_ID@" :date "@MAN_DATE@"

* NAME

mu query language -- a language for finding messages in *mu* databases.

* DESCRIPTION

The mu query language is a language used by *mu find* and *mu4e* to find messages in
*mu*'s Xapian databases. The language is quite similar to Xapian's default
query-parser, but is an independent implementation that is customized for the
mu/mu4e use-case.

In this article, we give a structured but informal overview of the query
language and provide examples.

As a companion to this, we recommend the *mu fields* and *mu flags* commands to get
an up-to-date list of the available fields and flags.

*NOTE:* if you use queries on the command-line (say, for *mu find*), you need to
quote any characters that would otherwise be interpreted by the shell, such as
*""*, *(* and *)* and whitespace.

* TERMS

The basic building blocks of a query are *terms*; these are just normal words like
'banana' or 'hello', or words prefixed with a field-name which make them apply
to just that field. See *mu find* for all the available fields.

Some example queries:
#+begin_example
vacation
subject:capybara
maildir:/inbox
#+end_example

Terms without an explicit field-prefix, (like 'vacation' above) are interpreted
like:
#+begin_example
to:vacation or subject:vacation or body:vacation or ...
#+end_example

The language is case-insensitive for terms and attempts to 'flatten' any
diacritics, so =angtrom= matches =Ångström=.

If terms contain whitespace, they need to be quoted:
#+begin_example
subject:"hi there"
#+end_example
This is a so-called =phrase query=, which means that we match against subjects
that contain the literal phrase "hi there".

Remember that you need to escape those quotes when using this from the
command-line:
#+begin_example
mu find subject:\\"hi there\\"
#+end_example

* LOGICAL OPERATORS

We can combine terms with logical operators -- binary ones: *and*, *or*, *xor* and the
unary *not*, with the conventional rules for precedence and association, and are
case-insensitive.


You can also group things with *(* and *)*, so you can do things like:
#+begin_example
(subject:beethoven or subject:bach) and not body:elvis
#+end_example

If you do not explicitly specify an operator between terms, *and* is implied, so
the queries
#+begin_example
subject:chip subject:dale
#+end_example
#+begin_example
subject:chip AND subject:dale
#+end_example
are equivalent. For readability, we recommend the second version.

Note that a =pure not= - e.g. searching for *not apples* is quite a 'heavy' query.

* REGULAR EXPRESSIONS AND WILDCARDS

The language supports matching basic PCRE regular expressions, see *pcre(3*).

Regular expressions are enclosed in *//*. Some examples:
#+begin_example
subject:/h.llo/		# match hallo, hello, ...
subject:/
#+end_example

Note the difference between 'maildir:/foo' and 'maildir:/foo/'; the former
matches messages in the '/foo' maildir, while the latter matches all messages in
all maildirs that match 'foo', such as '/foo', '/bar/cuux/foo', '/fooishbar'
etc.

Wildcards are an older mechanism for matching where a term with a rightmost ***
(and =only= in that position) matches any term that starts with the part before
the ***; they are supported for backward compatibility and *mu* translates them to
regular expressions internally:
#+begin_example
foo*
#+end_example
is equivalent to
#+begin_example
/foo.*/
#+end_example

As a note of caution, certain wild-cards and regular expression can take quite a
bit longer than 'normal' queries.

* FIELDS

We already saw a number of search fields, such as *subject:* and *body:*. For the
full table with all details, including single-char shortcuts, try the command:
~mu info fields~.

|------------+-----------+--------------------------------|
| field-name | alias     | description                    |
| bcc        |           | Blind carbon-copy recipient    |
| body       |           | Message plain-text body        |
| cc         |           | Carbon-copy recipient          |
| changed    |           | Last change time               |
| date       |           | Message date                   |
| embed      |           | Embedded text                  |
| file       |           | Attachment file name           |
| flags      | flag      | Message properties             |
| from       |           | Message sender                 |
| language   | lang      | ISO 639-1 language code (*)    |
| maildir    |           | Maildir path for message       |
| list       |           | Mailing list (List-Id:)        |
| message-id | msgid     | Message-Id                     |
| mime       | mime-type | Attachment MIME-type           |
| path       |           | File system path to message    |
| priority   | prio      | Priority                       |
| references |           | References to related messages |
| size       |           | Message size in bytes          |
| subject    |           | Message subject                |
| tags       | tag       | Message tags                   |
| thread     |           | Thread a message belongs to    |
| to         |           | Message recipient              |
|------------+-----------+--------------------------------|

(*) The language code for the text-body if found. This works only
if ~mu~ was built with CLD2 support.

There are also the special fields *contact:*, which matches all contact-fields
(=from=, =to=, =cc= and =bcc=), and *recip*, which matches all recipient-fields (=to=, =cc=
and =bcc=).

Hence, for instance,
#+begin_example
contact:fnorb@example.com
#+end_example
is equivalent to
#+begin_example
(from:fnorb@example.com or to:fnorb@example.com or
      cc:from:fnorb@example.com or bcc:fnorb@example.com)
#+end_example

* DATE RANGES

The *date:* field takes a date-range, expressed as the lower and upper bound,
separated by *..*. Either lower or upper (but not both) can be omitted to create
an open range.

Dates are expressed in local time and using ISO-8601 format (YYYY-MM-DD
HH:MM:SS); you can leave out the right part, and *mu* adds the rest, depending on
whether this is the beginning or end of the range (e.g., as a lower bound,
'2015' would be interpreted as the start of that year; as an upper bound as the
end of the year).

You can use '/' , '.', '-' and 'T' to make dates more human readable.

Some examples:
#+begin_example
date:20170505..20170602
date:2017-05-05..2017-06-02
date:..2017-10-01T12:00
date:2015-06-01..
date:2016..2016
#+end_example

You can also use the special 'dates' *now* and *today*:
#+begin_example
date:20170505..now
date:today..
#+end_example

Finally, you can use relative 'ago' times which express some time before now and
consist of a number followed by a unit, with units *s* for seconds, *M* for minutes,
*h* for hours, *d* for days, *w* for week, *m* for months and *y* for years. Some
examples:

#+begin_example
date:3m..
date:2017.01.01..5w
#+end_example

* SIZE RANGES

The *size* or *z* field allows you to match =size ranges= -- that is, match messages
that have a byte-size within a certain range. Units (b (for bytes), K (for 1000
bytes) and M (for 1000 * 1000 bytes) are supported). Some examples:

#+begin_example
size:10k..2m
size:10m..
#+end_example

* FLAG FIELD

The *flag/g* field allows you to match message flags. The following fields are
available:
#+begin_example
	a,attach        Message with attachment
	d,draft         Draft Message
	f,flagged       Flagged
	l,list          Mailing-list message
	n,new           New message (in new/ Maildir)
	p,passed        Passed ('Handled')
	r,replied       Replied
	s,seen          Seen
	t,trashed       Marked for deletion
	u,unread        new OR NOT seen
	x,encrypted     Encrypted message
	z,signed        Signed message
#+end_example

Some examples:
#+begin_example
flag:attach
flag:replied
g:x
#+end_example

Encrypted messages may be signed as well, but this is only visible after
decrypting and thus invisible to *mu*.

* PRIORITY FIELD

The message priority field (*prio:*) has three possible values: *low*, *normal* or
*high*. For instance, to match high-priority messages:
#+begin_example
prio:high
#+end_example

* MAILDIR

The Maildir field describes the directory path starting *after* the Maildir-base
path, and before the =/cur/= or =/new/= part. So for example, if there's a message
with the file name =~/Maildir/lists/running/cur/1234.213:2,=, you could find it
(and all the other messages in the same maildir) with:
#+begin_example
maildir:/lists/running
#+end_example

Note the starting '/'. If you want to match mails in the 'root' maildir, you can
do with a single '/':
#+begin_example
maildir:/
#+end_example

If you have maildirs (or any fields) that include spaces, you need to quote
them, ie.
#+begin_example
maildir:"/Sent Items"
#+end_example

Note that from the command-line, such queries must be quoted:
#+begin_example
mu find 'maildir:"/Sent Items"'
#+end_example

* MORE EXAMPLES

Here are some simple examples of *mu* queries; you can make many more complicated
queries using various logical operators, parentheses and so on, but in the
author's experience, it's usually faster to find a message with a simple query
just searching for some words.

Find all messages with both 'bee' and 'bird' (in any field)
#+begin_example
bee AND bird
#+end_example

Find all messages with either Frodo or Sam:
#+begin_example
Frodo OR Sam
#+end_example

Find all messages with the 'wombat' as subject, and 'capybara' anywhere:
#+begin_example
subject:wombat and capybara
#+end_example

Find all messages in the 'Archive' folder from Fred:
#+begin_example
from:fred and maildir:/Archive
#+end_example

Find all unread messages with attachments:
#+begin_example
flag:attach and flag:unread
#+end_example

Find all messages with PDF-attachments:
#+begin_example
mime:application/pdf
#+end_example

Find all messages with attached images:
#+begin_example
mime:image/*
#+end_example

Find all messages written in Dutch or German with the word 'hallo':
#+begin_example
hallo and (lang:nl or lang:de)
#+end_example


* CAVEATS

With current Xapian versions, the apostroph character is considered part of a
word. Thus, you cannot find =D'Artagnan= by searching for =Artagnan=. So, include
the apostrophe in search or use a regexp search.

Matching on spaces has changed compared to the old query-parser; this applies
e.g. to Maildirs that have spaces in their name, such as =Sent Items=. See *MAILDIR*
above.

#+include: "prefooter.inc" :minlevel 1

* SEE ALSO

*mu-find(1)*, *mu-info(1), *pcre(3)*
