I am building a query covering several WHERE AND conditions. Here is an example:
...
WHERE stage1 = 3
AND stage2 = 3
AND stage3 = 3
AND stage4 = 3
AND stage5 = 3
AND submitted = 0
Is there a shorter way of writing this, perhaps like WHERE TRUE(stage1=3 & stage2=3 ...) ?
Edit - just for info, here's the table:
The shorter way to write that would be:
WHERE (stage1, stage2, stage3, stage4, stage5, submitted)
= (3, 3, 3, 3, 3, 0)
It won't be any faster though, either way you write it.
No, there is not. And the notation you suggest is not really shorter. :)
Why would you need it to be shorter, and what table structure do you have where all these stage fields should be 3?
[edit] Added a solution for querying stages from a hypothetical detail table.
select
*
from
FormsTable f
where
f.submitted = 0 and
not exists
(select 'x'
from
PageDetailTable d
where
d.FormId = f.FormId and
d.State <> 3)
This is hardly shorter at the moment, but when you get more complex form that consist of more (or less) pages, you can support this more easily. When you create a form, you create a record for each page it consists of. In the page record you can store not only the state, but also other data you may need. When you get a different type of form with more or less pages, you can just create those pages. This query just checks if the form is not submitted and if it doesn't have any pages that are not finished yet. It doesn't matter how many pages there are.
Related
I'm trying to find unaccounted for numbers within a substantially large SQL dataset and facing some difficulty sorting.
By default the data for column reads
'Brochure1: Brochure2: Brochure3:...Brochure(k-1): Brochure(k):'
where k stands in for the number of brochures a unique id is eligible for.
Now the issue arises as the brochures are accounted for a sample updated data would read
'Brochure1: 00001 Brochure2: 00002 Brochure3: 00003....'
How does one query out the missing numbers, if in the range of number of say 00001-88888 some haven't been accounted next to Brochure(X):
The right way:
You should change the structure of your database. If you care about performance, you should follow the good practices of relational databases, so as first comment under your question said: normalize. Instead of placing information about brochures in one column of the table, it's much faster and more clear solution to create another table, that will describe relations between brochures and your-first-table-name
<your-first-table-name>_id | brochure_id
----------------------------+---------------
1 | 00002
1 | 00038
1 | 00281
2 | 28192
2 | 00293
... | ...
Not mention, if possible - you should treat brochure_id as integer, so using 12 instead of 0012.
The difference here is, that now you can make efficient and simple queries, to find out how many brochures one ID from your first table has, or what ID any brochure belongs to. If for some reason you need to keep the ordinal number of every single brochure you can add a column to the above table, like brochure_number.
What you want to achieve (not recommended): I think the fastest way to achieve your objective without changing the db structure, is to get the value of your brochures column, and then process it with your script. You really don't want to create a SQL statement to parse this kind of data. In PHP that wolud look something like this:
// Let's assume you already have your `brochures` column value in variable $brochures
$bs = str_replace(": ", ":", $brochures);
$bs = explode(" ", $bs);
$brochures = array();
foreach($bs as $b)
$brochures[substr($b, 8, 1)] = substr($b, strpos($b, ":")+1, 5);
// Now you have $brochures array with keys representing the brochure number,
// and values representing the ID of brochure.
if(isset($brochures['3'])){
// that row has a defined Brochure3
}else{
// ...
}
I have a question about how to query a 'checkboxWizard' BLOB field. In have added a such field to tl_member. This is working very fine. I can add “0 to N” selection to each members. Let’s call this field “myBlob”.
Now the questions is how to query “myBlob” with the Contao way? Let’s say I want all member that are in the postal code “12120” and that have the id “2” of “myBlob” selected. Not only “2” but at least this one.
$arrColumn[] = "tl_member.postal=?";
$arrValues[] = 12120;
$arrColumn[] = "tl_member.myBlob=?"; <- how to say “contains in the blob” here?
$arrValues[] = 2;
self::findBy($arrColumn, $arrValues)
The only way to do this (when using the default Contao method for such relationships) is to create a query like:
… WHERE myBlob LIKE '%"2"%'
So in your case it might be:
$arrColumn[] = "tl_member.myBlob LIKE ?";
$arrValues[] = '%"2"%';
However, this is of course cumbersome and might not work in all cases.
May be a better way would be to use codefog/contao-haste with its 'many to many' helper: https://github.com/codefog/contao-haste/blob/master/docs/Model/index.md
This way you will have a separate table containing the references.
I have a couple systems which contain a users' table along with some form of karma/weight/reputation. Sometimes it's the number of posts a user has made, sometimes it's the number of up/down votes a user has received across all their activity on the site.
USER {
id int
name string
karma int
}
How do I use these numbers to calculate that user's "weight" or "authority"? For example, the vote of one long-time member is often worth much more than 4 votes from brand new users.
I was thinking about adding up the total points/karma/reputation of all members and then trying to come up with a 1-100 scale.
SUM(user.points) / COUNT(user.*) = average user points
Then something like
CEIL(userA.points / average user points) = their weight on an issue
However, there also needs to be a curve on the points this way as I don't want someone with 5,000 posts/karma to out weigh 20 new users votes.
Mathematically, your best bet is to weight by the log of the percentile ranking of user in question. However, that is painful in SQL.
Simpler would be to cheat and assume the mean is the same as the median (a very bad assumption statistically, but much simpler programmatically):
SELECT 1 - log10(SELECT COUNT (*) FROM user
WHERE (SUM(user.points) / COUNT(user.*)) < user.points)
/ SELECT (COUNT (*) from user))
In this way, your top 10% of karma would have one and a half the impact of your average user, almost twice the impact of a noob.
Changing the log base would scale this, obviously, where natural log (log() in mysql) would give the upper 10% 3 times as much impact as a noob, and twice the impact as average. Log2() is even more extreme. (Note: subtraction is required because the log will be negative.)
If you want a more severe effect you might try squaring the log. (Note: squaring makes the log squared positive, so addition is appropriate here.)
If you want a hyperprecise rule, you can go into standard deviations, but the sql gets cumbersome and slow. It all depends on how far down the rabbit hole you want to go....
There are probably some resources that can provide you with parameters for this, but you should probably decide exactly what you want rather than using some predefined model. I suggest you define some rules for which sets of users should be equivalent or which should outweigh each other (e.g. 10 0 karma users = 1 5k karma user) (equivalence is much easier to work with), which will very quickly produce parameters for some chosen equation.
Using log (as already suggested), some (fractional) power (like square root) or even just linear can work.
I suggest something like newKarma = a.karma^b + c, and it shouldn't be to difficult to solve a, b and c. I suggest you pick b rather than trying to calculate it. Using new users (with karma = 0) should make this quite easy to solve. Guessing values to get close to what you want can be easier than determining them mathematically (since some rules together won't fit any simple equation).
Note that c above is an offset to karma, which will give many new users more total karma than high-karma users. You may also want to think about a.(karma + c)^b, or a.(karma + c)^b + d. Analysing the rules you defined should tell you which one to use.
UPDATE: Added alternatives for c
EDIT: You have some options for SQL. A temp table (with sums) might actually be the fastest. You can also just use a view. A join on the same table might also be possible, though I'm not sure. Using a view would look something like: (for some chosen a,b,c and d) (you may also want to add indices to the view)
Votes(issueID, userID) // table structure
User(userID, karma, ...) // table structure
CREATE VIEW Sums AS
SELECT issueID, SUM(1*POWER(karma + 2, 3) + 4) AS sumVal
FROM Votes JOIN User ON User.userID = Votes.userID
GROUP BY issueID
Query:
SELECT (1*POWER(karma + 2, 3) + 4)/sumVal AS influenceOnIssue
FROM Votes JOIN User ON User.userID = Votes.userID
JOIN Sums on Sums.issueID = Votes.issueID
WHERE Votes.userID = #UserID AND Votes.issueID = #IssueID
A simplification may be to have a computed column that = 1*POWER(karma + 2, 3) + 4
The faster option would be to calculate the derived karma on insert/update, either by having an additional column and using triggers or just calculating in before you call insert/update, and calling insert/update with the new value.
I am trying to make use of the mobile device lookup data in the WUFL database at http://wurfl.sourceforge.net/smart.php but I'm having problems getting my head around the MySQL code needed (I use Coldfusion for the server backend). To be honest its really doing my head in but I'm sure there is a straightforward approach to this.
The WUFL is supplied as XML (approx 15200 records to date), I have the method written that saves the data to a MySQL database already. Now I need to get the data back out in a useful way!
Basically it works like this: firstly run a select using the userAgent data from a CGI pull to match against a known mobile device (row 1) using LIKE; if found then use the resultant fallback field to look up the default data for the mobile device's 'family root' (row 2). The two rows need to be combined by overwriting the contents of (row 2) with the specific mobile device's features of (row 1). Both rows contain NULL entries and not all the features are present in (row 1).
I just need the fully populated row of data returned if a match is found. I hope that makes sense, I would provide what I think the SQL should look like but I will probably confuse things even more.
Really appreciate any assistance!
This would be my shot at it in SQL Server. You would need to use IFNULL instead of ISNULL:
SELECT
ISNULL(row1.Feature1, row2.Feature1) AS Feature 1
, ISNULL(row1.Feature2, row2.Feature2) AS Feature 2
, ISNULL(row1.Feature3, row2.Feature3) AS Feature 3
FROM
featureTable row1
LEFT OUTER JOIN featureTable row2 ON row1.fallback = row2.familyroot
WHERE row1.userAgent LIKE '%Some User Agent String%'
This should accomplish the same thing in MySQL:
SELECT
IFNULL(row1.Feature1, row2.Feature1) AS Feature 1
, IFNULL(row1.Feature2, row2.Feature2) AS Feature 2
, IFNULL(row1.Feature3, row2.Feature3) AS Feature 3
FROM
featureTable AS row1
LEFT OUTER JOIN featureTable AS row2 ON row1.fallback = row2.familyroot
WHERE row1.userAgent LIKE '%Some User Agent String%'
So what this does, is takes your feature table, aliases it as row1 to get your specific model features. We then join it back to itself as row2 to get the family features. Then the ISNULL function says "if there is no Feature1 value in row 1 (it's null) then get the Feature1 value from row2".
Hope that helps.
We want to set up a directory of all the organizations working with us. They are incredibly diverse (government, embassy, private companies, and organizations depending on them ). So, I've resolved to create 2 tables. Table 1 will treat all the organizations equally, i.e. it'll collect all the basic information (name, address, phone number, etc.). Table 2 will establish the hierarchy among all the organizations. For instance, Program for illiterate adults depends on the National Institute for Social Security which depends on the Labor Ministry.
In the Hierarchy table, each column represents a level. So, for the example above, (i)Labor Ministry - Level1(column1), (ii)National Institute for Social Security - Level2(column2), (iii)Program for illiterate adults - Level3(column3).
To attach an organization to an hierarchy, the user needs to go level by level(i.e. column by column). So, there will be at least 3 situations:
If an adequate hierarchy exists for an organization(for instance, level1: US Embassy), that organization can be added (For instance, level2: USAID).--> US Embassy/USAID, and so on.
How about if one or more levels are missing? - then they need to be added
How about if the hierarchy need to be modified? -- not every thing need to be modified.
I do not have any choice but working by level (i.e. column by column). I does not make sense to have all the levels in one form as the user need to navigate hierarchies to find the right one to attach an organization.
Let's say, I have those queries in my repository (just that you get the idea).
Query1
var orgHierarchy = (from orgH in db.Hierarchy
select orgH.Level1).FirstOrDefault;
Query2
var orgHierarchy = (from orgH in db.Hierarchy
select orgH.Level2).FirstOrDefault;
Query3, Query4, etc.
The above queries are the same except for the property queried (level1, level2, level3, etc.)
Question: Is there a general way of writing the above queries in one? So that the user can track an hierarchy level by level to attach an organization.
In other words, not knowing in advance which column to query, I still need to be able to do so depending on some conditions. For instance, an organization X depends on Y. Knowing that Y is somewhere on the 3rd level, I'll go to the 4th level, linking X to Y.
I need to select (not manually) a column with only one query that takes parameters.
=======================
EDIT
As I just said to #Mark Byers, all I want is just to be able to query a column not knowing in advance which one. Check this out:
How about this
Public Hierarchy GetHierarchy(string name)
{
var myHierarchy = from hierarc in db.Hierarchy
where (hierarc.Level1 == name)
select hierarc;
retuen myHierarchy;
}
Above, the query depends on name which is a variable. It mighbe Planning Ministry, Embassy, Local Phone, etc.
Can I write the same query, but this time instead of looking to much a value in the DB, I impose my query to select a particular column.
var myVar = from orgH in db.Hierarchy
where (orgH.Level1 == "Government")
select orgH.where(level == myVariable);
return myVar;
I don't pretend that select orgH.where(level == myVariable) is even close to be valid. But that is what I want: to be able to select a column depending on a variable (i.e. the value is not known in advance like with name).
Thanks for helping
How about using DynamicQueryable?
http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
Your database is not normalized so you should start by changing the heirarchy table to, for example:
OrganizationId Parent
1 NULL
2 1
3 1
4 3
To query this you might need to use recursive queries. This is difficult (but not impossible) using LINQ, so you might instead prefer to create a parameterized stored procedure using a recursive CTE and put the query there.