I have a DB table named games which lets just say for simplification contains the columns "id" and "gametitle" and has roughly 7,000 rows already populated.
What I would like to do is have a piece of SQL that would generate a SEF alias for the gametitle that I can use in the URL (I have URL Rewriting successfully running on the site).
The new field would be entered into a new column named "gamealias".
So for instance, if I had a gametitle of "Halo: Combat Evolved" it would drop any special characters and produce something similar to "halo-combat-evolved". All the aliases in the table would have to be unique as they are going to be used in the games url... e.g. http://thegamesdb.net/game/halo-combat-evolved/
Also, it would be nice if upon insertion of a new row, the alias could be generated automatically from SQL without having to handle it in PHP (maybe using the sql fields default value somehow), although I don't mind having to do this in PHP if it's not possible magically in SQL.
I think this could be done in MySQL using a trigger and a regex-replace UDF, but it would probably be a simpler route just using PHP. You could easily guarantee gamealias uniqueness if you integrated the title's primary key in with the string. For example, consider something that would output "halo-combat-evolved-321".
Related
i have an SQL table that you can add brand names to, and when a new brand name is added, it will either increase the existing brand active count, or create a new brand name.
The problem is, if someone added a new brand with different spelling (like adding Toyota but spelled toyota) it would make a new brand with a new active count and new brand id. Now that the table has a few instances of this, is there a way i can sort through with SQL and merge the similar brands? I know this would end up deleting a few rows and I'm not sure if SQL has the power to do this all at once.
I'm still kind of new to SQL so any advice on this is appreciated. I heard that using Python Pandas would be easier so I am currently looking into that for a method to do this.
In case of simple case changes, you can use functions like LOWER() to convert all of them to lower case and then group results together based on brand_name,
However, your question says "similar" records where similar is not so well defined. The SQL language expects you to clearly define what you need.
If you are looking to fix one / few characters you can use LIKE operator with percentage (%) and / or underscore (_) sign. You can define all permutations of errors you would like to identify by placing % and _ at various positions. Alternatively, you can also explore SOUNDEX function or sounds like in MySQL and see if you can merge brand names based on SOUNDEX.
If data is not huge, I will suggest you to create another table / temporary table to perform such operation. This way, you can always refer back to original data.
I'm building a MySQL event to make a copy of a table in the database with a timestamp in the name.
CREATE TABLE `db_name`.`tbl_prefix_(SELECT TO_SECONDS(NOW()))` ( [the rest...]
Obviously this isn't working. What should I do to make it work?
Any suggestions are welcome.
Thanks
This is a bad architecture. Generating tables on the fly is not something you should do.
Instead, create a single table with a timestamp column. For instance, if you would before have 3 tables with three timestamps A, B, and C, you now have one table with a timestamp column containing the values A, B, and C, respectively.
In order to do this, you would need to use "dynamic SQL". That is, make use of the MySQL PREPARE statement.
What you'd need to do is populate a variable with a string that contains the SQL text you want to execute. Doing variable substitution into string is trivial.
The "trick" is to take that dynamic string and execute it like it was a SQL statement.
And that's what the PREPARE statement does for us, takes in a variable, and reads the contents of that variable like it were a SQL statement.
With that said, rather than give an example code that demonstrates this in more detail, I'm going to suggest that you re-think this idea of creating a table with timestamp value as part of the name.
What problem is that designed to solve? And carefully consider whether the proposed design for a solution will introduce a bigger problem than it solves.
I have a table in the database with the following columns: ID, Name, Txt. We are using Linq To Sql to implement our DAL. In there another collegue added two extra columns so in the code the same table results: ID, Name, Txt, NameTemp, TxtTemp.
These two "fake" tables are used in different parts of the code in LINQ joins and analyzing with SQL Profiler the parsed SQL query takes the "real" columns and everything works properly.
Now I need to make an INSERT using that table, but I get an exception since also the fake columns are used in the statement.
Since I cannot add the two fake columns in the DB(since unuseful there), is there a way in which I could make an insert with Linq omitting these two columns?
I think i know where you're getting at. You should be able to add properties to a partial linq class no problem, only thing is that if you try and use a linq query against these "fake" columns, you'll get an exception when linqtosql tries to reference a column that doesn't exist in the database. I've been through this before - i wanted to be able to select columns that don't exist in the database (but do in the linq2sql dbml class) and have linq2sql translate the columns into what they really are in the database. Only problem is that there's no real easy way to do this - you can add attributes to the "fake" properties so that linq2sql thinks that NameTmp and TxtTmp are in fact Name and Txt in the sql world, only problem is that when it comes to inserting a record, the translated sql specifies the same column twice (which SQL doesn't like and throws an exception).
You can mark the column with IsDbGenerated = true - that'll let you insert records without getting the double column problem, but you can't update a record without linqtosql complaining that you can't update a computed column. I guess you can use a sproc to get around this perhaps?
I logged a bug with Microsoft a while back, which they'll never fix. The info here might help you get what you need -
http://social.msdn.microsoft.com/Forums/eu/linqtosql/thread/5691e0ad-ad67-47ea-ae2c-9432e4e4bd46
https://connect.microsoft.com/VisualStudio/feedback/details/526402/linq2sql-doesnt-like-it-when-you-wrap-column-properties-with-properties-in-an-interface
LINQ is not for inserting data, but for querying only - Language INtegrated Query. Use ADO.NET for inserting the data.
(Leaving the first part to remind my stupidity)
Check ScottGu. The classes generated are partial (mentioned here), so you can put your 2 properties into the editable part and since they won't have any mapping attribute defined, they won't be mapped nor persisted.
I have a field called 'click_target' that stores a string of data similar to this:
http://domain.com/deals/244?utm_source=sendgrid.com&utm_medium=email&utm_campaign=website
Using a MySQL query, is it possible to pull the ID (244) from the string and use it to join another table?
You can certainly play games with expressions to pull the ID out of this string but I have a bigger worry - you're burning a dependency on the URL format into a query in the database. That's not really a good idea becuase when (I don't say IF) the URL's change your queries will suddenly fail silently - no errors, just empty (if you're lucky) or nonsensical results.
It's an ugly hack, but I believe this line will extract your ID for you in the above url.
REVERSE(LEFT(LOCATE('/', REVERSE(LEFT(click_target, LOCATE('?', click_target)-1)))-1))
Basically, I am getting the text between the first '?' and the last '/'. From there you can join on whatever table you want with that value, though I recommend aliasing it or storing it in a variable so that it is not recalculated frequently.
If you need the id, fix your database to store it porperly in a separate field.
I need to extract the following fields into a new table. Any ideas whether I can do this exclusively with a query or I need to use PHP as well?
Current table structure
USERID USEREXPERINCE
1 a:4:{i:0;s:20:"business development";i:1;s:6:"design";i:2;s:9:"marketing";i:3;s:15:"press relations";}
Required table structure
USERID USEREXPERINCE
1 business development
1 design
1 marketing
1 press relations
2 web development
2 design
3 marketing
3 business development
Thanks.
You need to use PHP - the 'LONGTEXT' data is in fact a serialized PHP array.
Execute the following to see what I mean:
<?php
print_r(unserialize('a:4:{i:0;s:20:"business development";i:1;s:6:"design";i:2;s:9:"marketing";i:3;s:15:"press relations";}'));
?>
As such, the easiest thing to do would be to read each row from the database, unserialize the data and insert it into a new table with the required fields. (I'm guessing you need to search on these, hence the need to store them as dedicated fields.)
That said, the serialized string you provided only appears to be storing IDs -> Field names (rather than any values), so I'm not sure what's going on there.
I would use PHP for this, simply because it is easier to call unserialize() and generate new INSERT statements than to parse the string in a MySQL procedure (though that could also be done). Also beware if your USERID column is currently a primary key, since it cannot be with the new structure.