How can it implement this in pymongo?
number == 100 or (number >=10000 and number < 10100)?
currently, I am doing it with
*condition['number'] = {'$gte':input_number * 100, '$lt':(input_number + 1) * 100}*
and then query with the condition.
But I don't know how to add "number == 100". Thanks!
The answer is:
condition['$where'] = '(this.number + "").substr(0, 3) == "%d"' % input_number
All I learnt from this is, you can do the query with where and the content for where is a javascript function or something.
But please note that this stupid method is quite slow.
Related
Given I have two a Table with Two string columns:
A
B
John likes to go jumpping
Max likes swimming but he also likes to go jummping
John is cool
max is smart
John
max
In Big-query SQL How can I find the longest common substring? such that I get
A
B
C
John likes to go jumping
Max likes swimming but he also likes to go jumping
likes to go jumping
John is cool
max is smart
is
John
max
null
Try below very much SQL'ish approach
select A, B,
(
select string_agg(word, ' ' order by a_pos) phrase
from unnest(split(A, ' ')) word with offset a_pos
join unnest(split(B, ' ')) word with offset b_pos
using(word)
group by b_pos - a_pos
order by length(phrase) desc
limit 1
) as C
from `project.dataset.table`
when applied to sample data in your question - output is
Obviously your example is very simple, so in real use case you might need to adjust above to reflect reality
Also, note: there are many other options/approaches for your problem that SO has already multiple answers for, including mine - for text similarity mostly based on using JS UDF and levenshtein distance or similar algorithms
This probably is not a problem for your SQL to solve (it is though very simple to solve via any scripting language). However, BigQuery does support JS based UDFs, which usually come in handy to solve such problems.
Here is an option (which at its core is not SQL) that you can take in BigQuery:
CREATE TEMP FUNCTION lcsub(a string, b string)
RETURNS STRING
LANGUAGE js AS """
a = a.split(' ');
b = b.split(' ');
let la = a.length;
let lb = b.length;
let output = [];
for (var i=0; i<la; i++){
for (var j=0; j<lb; j++){
if (a[i] == b[j]){
let u = [b[j]]
let aidx = i;
for (var k = j+1; k<lb; k++){
u.push(b[k]);
if (u.join(' ') == a.slice(i, aidx +1+1).join(' ')){
if (u.length >= output.length){
output = u;
}
}
else {
u.pop();
if (u.length >= output.length){
output = u;
}
break;
}
aidx += 1;
if (aidx > la -1){
break
}
}
}
}
}
return output.join(' ')
""";
select A, B, lcsub(A, B) as C from dataset.table
Hi im trying to do an event alarms system that It is thought to depend on a list of undeterminated concatened conditional rules. Here comes my logical problem, when im trying to structure the database to save this conditional rules in a table, i cant figure out how exactly trace the hierarchy of the expressions, for example if i wanna save the conditión
[(1 =< 2 && 2 == 2) || (0 == 0 || 1 == 1)] && (1 == 1) or any undeterminated number of concatened conditional rules. Can anybody help o almost understand me ?
P.D: Sorry my bad english (:
I'm trying to use .extra() where the query return more than 1 result, like :
'SELECT "books_books"."*" FROM "books_books" WHERE "books_books"."owner_id" = %s' % request.user.id
I got an error : only a single result allowed for a SELECT that is part of an expression
Try it on dev-server using sqlite3. Anybody knows how to fix this? Or my query is wrong?
EDIT:
I'm using django-simple-ratings, my model like this :
class Thread(models.Model):
#
#
ratings = Ratings()
I want to display each Thread's ratings and whether a user already rated it or not. For 2 items, it will hit 6 times, 1 for the actual Thread and 2 for accessing the ratings. The query:
threads = Thread.ratings.order_by_rating().filter(section = section)\
.select_related('creator')\
.prefetch_related('replies')
threads = threads.extra(select = dict(myratings = "SELECT SUM('section_threadrating'.'score') AS 'agg' FROM 'section_threadrating' WHERE 'section_threadrating'.'content_object_id' = 'section_thread'.'id' ",)
Then i can print each Thread's ratings without hitting the db more. For the 2nd query, i add :
#continue from extra
blahblah.extra(select = dict(myratings = '#####code above####',
voter_id = "SELECT 'section_threadrating'.'user_id' FROM 'section_threadrating' WHERE ('section_threadrating'.'content_object_id' = 'section_thread'.'id' AND 'section_threadrating'.'user_id' = '3') "))
Hard-coded the user_id. Then when i use it on template like this :
{% ifequal threads.voter_id user.id %}
#the rest of the code
I got an error : only a single result allowed for a SELECT that is part of an expression
Let me know if it's not clear enough.
The problem is in the query. Generally, when you are writing subqueries, they must return only 1 result. So a subquery like the one voter_id:
select ..., (select sectio_threadrating.user_id from ...) as voter_id from ....
is invalid, because it can return more than one result. If you are sure it will always return one result, you can use the max() or min() aggregation function:
blahblah.extra(select = dict(myratings = '#####code above####',
voter_id = "SELECT max('section_threadrating'.'user_id') FROM 'section_threadrating' WHERE ('section_threadrating'.'content_object_id' = 'section_thread'.'id' AND 'section_threadrating'.'user_id' = '3') "))
This will make the subquery always return 1 result.
Removing that hard-code, what user_id are you expecting to retrieve here? Maybe you just can't reduce to 1 user using only SQL.
I've got myself in a bit of a pickle!
I've done a snazzy LINQ statement that does the job in my web app, but now I'd like to use this in a stored procedure:
var r = (from p in getautocompleteweightsproducts.tblWeights
where p.MemberId == memberid &&
p.LocationId == locationid
select p);
if (level != "0")
r = r.Where(p => p.MaterialLevel == level);
if (column == "UnitUserField1")
r = r.Where(p => p.UnitUserField1 == acitem);
if (column == "UnitUserField2")
r = r.Where(p => p.UnitUserField2 == acitem);
return r.OrderBy(p => p.LevelNo).ToList();
However, I can't for the life of me get the conditional where clause to work!!
If someone can point me in the right direction, I'd be most grateful.
Kind regards
Maybe something like this?
SELECT *
FROM dbo.weights
WHERE member_id = #memberid
AND location_id = #locationid
AND material_level = CASE WHEN #level = '0' THEN material_level
ELSE #level END
AND #acitem = CASE #column WHEN 'UnitUserField1' THEN unit_user_field_1
WHEN 'UnitUserField2' THEN unit_user_field_2
ELSE #acitem END
ORDER BY level_no
Have you tried LinqPAD, I'm pretty sure last time I played with that you could enter "LINQ to SQL" code and see the resulting SQL that produced. Failing that, place a SQL trace/profiler on your code running the LinqTOSQL and find the query being executed in the trace.
LukeH's answer will give you the correct rows, but there is something lost when you try to replace a query-generating-machine with a single query. There are parts of that query that are opaque to the optimizer.
If you need the original queries as-would-have-been-generated-by-linq, there are two options.
Generate every possible query and control which one runs by IF ELSE.
Use Dynamic sql to construct each query (although this trades away many of the benefits of using a stored procedure).
If you do decide to use dynamic sql, you should be aware of the curse and blessings of it.
I use codeigniter and have an issue about SELECT MAX ... I couldnot find any solution at google search...
it looks like it returns only id :/ it's giving error for other columns of table :/
Appreciate helps, thanks!
Model:
function get_default()
{
$this->db->select_max('id');
$query = $this->db->getwhere('gallery', array('cat' => "1"));
if($query->num_rows() > 0) {
return $query->row_array(); //return the row as an associative array
}
}
Controller:
$default_img = $this->blabla_model->get_default();
$data['default_id'] = $default_img['id']; // it returns this
$data['default_name'] = $default_img['gname']; // it gives error for gname although it is at table
To achieve your goal, your desire SQL can look something like:
SELECT *
FROM gallery
WHERE cat = '1'
ORDER BY id
LIMIT 1
And to utilise CodeIgniter database class:
$this->db->select('*');
$this->db->where('cat', '1');
$this->db->order_by('id', 'DESC');
$this->db->limit(1);
$query = $this->db->get('gallery');
That is correct: select_max returns only the value, and no other column. From the specs:
$this->db->select_max('age');
$query = $this->db->get('members');
// Produces: SELECT MAX(age) as age FROM members
You may want to read the value first, and run another query.
For an id, you can also use $id = $this->db->insert_id();
See also: http://www.hostfree.com/user_guide/database/active_record.html#select
CodeIgniter will select * if nothing else is selected. By setting select_max() you are populating the select property and therefore saying you ONLY want that value.
To solve this, just combine select_max() and select():
$this->db->select('somefield, another_field');
$this->db->select_max('age');
or even:
$this->db->select('sometable.*', FALSE);
$this->db->select_max('age');
Should do the trick.
It should be noted that you may of course also utilize your own "custom" sql statements in CodeIgniter, you're not limited to the active record sql functions you've outlined thus far. Another active record function that CodeIgniter provides is $this->db->query(); Which allows you to submit your own SQL queries (including variables) like so:
function foo_bar()
{
$cat = 1;
$limit = 1;
$sql = "
SELECT *
FROM gallery
WHERE cat = $cat
ORDER BY id
LIMIT $limit
";
$data['query'] = $this->db->query($sql);
return $data['query'];
}
Recently I have been utilizing this quite a bit as I've been doing some queries that are difficult (if not annoying or impossible) to pull off with CI's explicit active record functions.
I realize you may know this already, just thought it would help to include for posterity.
2 helpful links are:
http://codeigniter.com/user_guide/database/results.html
http://codeigniter.com/user_guide/database/examples.html