I have a field where the user enters multiple values each separated by a comma eg "1.8, 2, 3".
I want to find the average of those values. Is there a way to utilise avg() to accommodate for stripping the comma and producing the mean?
Unfortunately you can't do that with the built in InfoPath functions (there is no traditional split method for strings).
If you are willing to tackle it - using managed code behind the form will very easily solve your problem (only about 4 lines of code). Basic math and string manipulation should not impose any security restrictions on the form. However you will have to setup for code behind which is easy but can seem like somewhat of a hassle the first time you try it. There are good MSDN articles on how to go about that.
Alternatively, if you can change your data entry from comma separated to a repeating table you can use the built in avg() function.
Related
I've got MySQL DB with multiple data in one column separated by semicolon. I need to use the first of them. What is the best recommended way how to deal with this kind of stored data? (for this specific problem and also generally how to use semicolon separated data).
Q: "What is the best recommended way how to deal with this kind of stored data?"
A: The best recommendation is to avoid storing data as comma separated lists. (And no, this does not mean we should use semicolons in place of commas as delimiters in the list.)
For an introductory discussion of this topic, I recommend a review of Chapter 2 in Bill Karwin's book: "SQL AntiPatterns: Avoiding the Pitfalls of Database Programming"
Which is conveniently available here
https://www.amazon.com/SQL-Antipatterns-Programming-Pragmatic-Programmers/dp/1934356557
and from other fine booksellers. Setting that recommendation aside for a moment...
To retrieve the first element from a semicolon delimited list, we can use the SUBSTRING_INDEX function.
As a demonstration:
SELECT SUBSTRING_INDEX('abc;def;ghi',';',1)
returns
'abc'
The MySQL SUBSTRING_INDEX function is documented here: https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_substring-index
I recognize that this might be considered a "link only answer". A good answer to this question is going to be much longer, giving examples to demonstrate the pitfall of storing comma separated lists.
If the database will only ever view the comma separated list as a blob of data, in its entirety, without a need to examine the contents of the list, then I would consider storing it, similar to the way we would store a .jpg image in the database.
I would store and retrieve a .jpg image as a BLOB, just a block of bytes, in its entirety. Save the whole thing, and retrieve the whole thing. I'm not ever going to have the database manipulate the contents of the image. I'm not going to ever ask the database to examine the image to discern information about what is "in" the jpg image. I'm not going to ask the database to derive any meaningful information out of it... How many people are in a photo, what are the names of people in a photo, add a person to the photo, and so on.
I will only condone storing a comma separated (or semicolon separated) separated list if we are intending it to be an object, an opaque block of bytes, like we handle a jpg image.
Use
SELECT SUBSTRING_INDEX(column_name, ';', 1) from your_table
I have a column which stores row information in a concatenate format such as:
LOCATION_COLUMN
[Country]*[city]*[town]
I want to extract the country )before the first aster ix part of it, [Country], while eliminating the [city][town]. I could complete this using a scripting language such as php which has great parsing tools, but if I could I like to complete the task inside of mysql. Looking at documentation I can't find any parsing techniques (there seem to be some parsing plugins for mysql), but I would like to keep the database as it is as it is used for many other things. Native sql syntax such as the commands LIKE I do not believe as be used as you need to know the characters you are looking for, but in my case I am not looking for specific characters, just want to extract the country parts. Is this somehow possible?
Assuming you mean that the components are separated by asterisks, you can use:
select substring_index(location_column, '*', 1) as country
Each returned transaction I am to report on is stored with a return reason code and a description of the return reason code. I built a tablix with two columns - one for return codes and another for descriptions. This works just peachy. The report owner is upset that a long list of codes will split pages - sigh. I was told to display them side-by-side.
I am new to t-sql and SSRS and its idiosyncrasies. I have minimal support from our DBAs. Two tables, filtered to display codes that meet a criteria sound simple enough.
My research:
MSDN's support network, Operators in Expressions page, and various help topics. I also found SO posts regarding split functions in t-sql and similar as well as one specifically asking about comparison and varchar. I found sites with helpful information like ResultData and Network Steve. I haven't found what I think I'm looking for.
My problem:
The return reason code is a varchar that always consists of the letter 'r' and two numeric digits (R00 to R99). It appears I can't run a comparison operator on an entire varchar that is alphanumeric; it doesn't recognize IIF((Fields!... <= R17),True,False). Additionally, the company will not allow the warehouse or its functions to be edited so I cannot create my own.
My solution ideas:
Add each Rnn code to the tablix filter, individually. This means ~50 filters per tablix and seems a sloppy or inefficient way of handling this
Separate the varchar string in to its alpha and numeric components and compare the latter using standard operators. This sounds the cleanest method but I'm unsure how to accomplish this in an expression or within SSRS
Forgo the two-table idea and create one table with four columns (code, description, code, description). This still leaves me with how to set a limit on the number of rows that can be created before 'spilling over' to the other side
I appreciate being pointed to any resources or any offered input to the issue and my (not so?)logical approach to it.
You can achieve your second option as follows:
CInt(Fields!ReturnCode.Value.Substring(1,2))
Let's assume I need to store some data of unknown amount within a database table. I don't want to create extra tables, because this will take more time to get the data. The amount of data can be different.
My initial thought was to store data in a key1=value1;key2=value2;key3=value3 format, but the problem here is that some value can contain ; in its body. What is the best separator in this case? What other methods can I use to be able to store various data in a single row?
The example content of the row is like data=2012-05-14 20:07:45;text=This is a comment, but what if I contain a semicolon?;last_id=123456 from which I can then get through PHP an array with corresponding keys and values after correctly exploding row text with a seperator.
First of all: You never ever store more than one information in only one field, if you need to access them separately or search by one of them. This has been discussed here quite a few times.
Assuming you allwas want to access the complete collection of information at once, I recommend to use the native serialization format of your development environment: e.g. if it is PHP, use serialze().
If it is cross-plattform, JSON might be a way to go: Good JSON encoding/decoding libraries exist for something like all environments out there. The same is true for XML, but int his context the textual overhead of XML is going to bite a bit.
On a sidenote: Are you sure, that storing the data in additional tables is slower? You might want to benchmark that before finally deciding.
Edit:
After reading, that you use PHP: If you don't want to put it in a table, stick with serialize() / unserialize() and a MEDIUMTEXT field, this works perfectly, I do it all the time.
EAV (cringe) is probably the best way to store arbitrary values like you want, but it sounds like you're firmly against additional tables for whatever reason. In light of that, you could just save the result of json_encode in the table. When you read it back, just json_decode to get it back into an array.
Keep in mind that if you ever need to search for anything in this field, you're going to have to use a SQL LIKE. If you never need to search this field or join it to anything, I suppose it's OK, but if you do, you've totally thrown performance out the window.
it can be the quotes who separate them .
key1='value1';key2='value2';key3='value3'
if not like that , give your sql example and we can see how to do it.
Is there any way to have MySQL order results by how close they 'sound' to a search term?
I'm trying to order fields that contain user input of city names. Variations and misspellings exist, and I'd like to show the 'closest' matches at the top.
I know soundex may not be the best algorithm for this, but if it (or another method) could be reasonable successful - it may be worth having the sorting done by the database.
Soundex is no good for this sort of thing because different words can give you the same Soundex results and will therefore sort arbitrarily. A better solution for this is the Levenshein Edit Distance algorithm and you may be able to implement it as a function in your database: Link to Levensheint impl. as MySql stored function!!!
You can also check out this SO link. It contains a Sql server (T-SQL-specific) implementation of the algorithm but it should be possible to port. The mechanics of the algorithm are fairly simple needing only a 2D array and looping over string.