Is there any easier way of writing sql to replace all columns names with "schedule_" to make it easier to work with in PHP.
SELECT * FROM schedules
Array
(
[schedule_id] => 9
[schedule_datetime_from] => 2011-12-22 18:28:00
[schedule_datetime_until] => 2011-12-22 22:28:00
[schedule_capacity] => 89
[schedule_amount] => 9.99
[content_id] => 77
)
At the moment I end up doing:
$stmnt1 = "SELECT s.schedule_id as id, s.schedule_datetime_from as datetime_from, s.schedule_datetime_until as datetime_until, etc FROM schedules s";
There is no other way to do this through SQL -- and really, why would you want to? It's not like you are typing in the query by hand each time.
What you could do is write PHP code that changes the array keys after each row has been read, but that's orders of magnitude worse as a solution. Just go with what you already have.
I agree with Jon, but if you REALLY have to get this done I would recommend using the MySQL command line interface. However, you must also consider indices, UNIQUE constraints, and Foreign Keys. And, if you have any code which is expecting the non-prefixed versions of the columns you will end up breaking it, so be sure your code is updated as well.
Read up on ALTER TABLE CHANGE via MySQL docs, the line you are looking for is: "You can rename a column using a CHANGE old_col_name new_col_name column_definition clause"
Related
The SQLite JSON1 extension has some really neat capabilities. However, I have not been able to figure out how I can update or insert individual JSON attribute values.
Here is an example
CREATE TABLE keywords
(
id INTEGER PRIMARY KEY,
lang INTEGER NOT NULL,
kwd TEXT NOT NULL,
locs TEXT NOT NULL DEFAULT '{}'
);
CREATE INDEX kwd ON keywords(lang,kwd);
I am using this table to store keyword searches and recording the locations from which the search was ininitated in the object locs. A sample entry in this database table would be like the one shown below
id:1,lang:1,kwd:'stackoverflow',locs:'{"1":1,"2":1,"5":1}'
The location object attributes here are indices to the actual locations stored elsewhere.
Now imagine the following scenarios
A search for stackoverflow is initiated from location index "2". In this case I simply want to increment the value at that index so that after the operation the corresponding row reads
id:1,lang:1,kwd:'stackoverflow',locs:'{"1":1,"2":2,"5":1}'
A search for stackoverflow is initiated from a previously unknown location index "7" in which case the corresponding row after the update would have to read
id:1,lang:1,kwd:'stackoverflow',locs:'{"1":1,"2":1,"5":1,"7":1}'
It is not clear to me that this can in fact be done. I tried something along the lines of
UPDATE keywords json_set(locs,'$.2','2') WHERE kwd = 'stackoverflow';
which gave the error message error near json_set. I'd be most obliged to anyone who might be able to tell me how/whether this should/can be done.
It is not necessary to create such complicated SQL with subqueries to do this.
The SQL below would solve your needs.
UPDATE keywords
SET locs = json_set(locs,'$.7', IFNULL(json_extract(locs, '$.7'), 0) + 1)
WHERE kwd = 'stackoverflow';
I know this is old, but it's like the first link when searching, it deserves a better solution.
I could have just deleted this question but given that the SQLite JSON1 extension appears to be relatively poorly understood I felt it would be more useful to provide an answer here for the benefit of others. What I have set out to do here is possible but the SQL syntax is rather more convoluted.
UPDATE keywords set locs =
(select json_set(json(keywords.locs),'$.**N**',
ifnull(
(select json_extract(keywords.locs,'$.**N**') from keywords where id = '1'),
0)
+ 1)
from keywords where id = '1')
where id = '1';
will accomplish both of the updates I have described in my original question above. Given how complicated this looks a few explanations are in order
The UPDATE keywords part does the actual updating, but it needs to know what to updatte
The SELECT json_set part is where we establish the value to be updated
If the relevant value does not exsit in the first place we do not want to do a + 1 on a null value so we do an IFNULL TEST
The WHERE id = bits ensure that we target the right row
Having now worked with JSON1 in SQLite for a while I have a tip to share with others going down the same road. It is easy to waste your time writing extremely convoluted and hard to maintain SQL in an effort to perform in-place JSON manipulation. Consider using SQLite in memory tables - CREATE TEMP TABLE... to store intermediate results and write a sequence of SQL statements instead. This makes the code a whole lot eaiser to understand and to maintain.
before i use alias for table i get the error:
: Integrity constraint violation: 1052 Column 'id' in field list is ambiguous
Then i used aliases and i get this error:
unknown index a
I am trying to get a list of category name ( dependant to a translation) and the associated category id which is unique. Since i need to put them in a select, i see that i should use the lists.
$categorie= DB::table('cat as a')
->join('campo_cat as c','c.id_cat','=','a.id')
->join('campo as d','d.id','=','c.id_campo')
->join('cat_nome as nome','nome.id_cat','=','a.id')
->join('lingua','nome.id_lingua','=','lingua.id')
->where('lingua.lingua','=','it-IT')
->groupby('nome.nome')
->lists('nome.nome','a.id');
The best way to debug your query is to look at the raw query Laravel generates and trying to run this raw query in your favorite SQL tool (Navicat, MySQL cli tool...), so you can dump it to log using:
DB::listen(function($sql, $bindings, $time) {
Log::info($sql);
Log::info($bindings);
});
Doing that with yours I could see at least one problem:
->where('lingua.lingua','=','it-IT')
Must be changed to
->where('lingua.lingua','=',"'it-IT'")
As #jmail said, you didn't really describe the problem very well, just what you ended up doing to get around (part of) it. However, if I read your question right you're saying that originally you did it without all the aliases you got the 'ambiguous' error.
So let me explain that first: this would happen, because there are many parts of that query that use id rather than a qualified table`.`id.
if you think about it, without aliases you query looks a bit like this: SELECT * FROM `cat` JOIN `campo_cat` ON `id_cat` = `id` JOIN `campo` ON `id` = `id_campo`; and suddenly, MySQL doesn't know to which table all these id columns refer. So to get around that all you need to do is namespace your fields (i.e. use ... JOIN `campo` ON `campo`.`id` = `campo_cat`.`id_campo`...). In your case you've gone one step further and aliased your tables. This certianly makes the query a little simpler, though you don't need to actually do it.
So on to your next issue - this will be a Laravel error. And presumably happening because your key column from lists($valueColumn, $keyColumn) isn't found in the results. This is because you're referring to the cat.id column (okay in your aliased case a.id) in part of the code that's no longer in MySQL - the lists() method is actually run in PHP after Laravel gets the results from the database. As such, there's no such column called a.id. It's likely it'll be called id, but because you don't request it specifically, you may find that the ambiguous issue is back. My suggestion would be to select it specifically and alias the column. Try something like the below:
$categories = DB::table('cat as a')
->join('campo_cat as c','c.id_cat','=','a.id')
->join('campo as d','d.id','=','c.id_campo')
->join('cat_nome as nome','nome.id_cat','=','a.id')
->join('lingua','nome.id_lingua','=','lingua.id')
->where('lingua.lingua','=','it-IT')
->groupby('nome.nome')
->select('nome.nome as nome_nome','a.id as a_id') // here we alias `.id as a_id
->lists('nome_nome','a_id'); // here we refer to the actual columns
It may not work perfectly (I don't use ->select() so don't know whether you pass an array or multiple parameters, also you may need DB::raw() wrapping each one in order to do the aliasing) but hopefully you get my meaning and can get it working.
I have this union statement when I try to take parameters from a form and pass it to a union select statement it says too many parameters. This is using MS ACCESS.
SELECT Statement FROM table 1 where Date = Between [Forms]![DateIN]![StartDate]
UNION
SELECT Statement FROM table 2 where Date = Between [Forms]![DateIN]![StartDate]
This is the first time I am using windows DB applications to do Database apps. I am Linux type of person and always use MySQL for my projects but for this one have to use MS Access.
Is there anther way to pass parameters to UNION Statement because this method of defining values in a form can work on Single SELECT statements. But I don't know why this problem exist.
Between "Determines whether the value of an expression falls within a specified range of values" like this ...
expr [Not] Between value1 And value2
But your query only gives it one value ... Between [Forms]![DateIN]![StartDate]
So you need to add And plus another date value ...
Between [Forms]![DateIN]![StartDate] And some_other_date
Also Date is a reserved word. If you're using it as a field name, enclose it in brackets to avoid confusing the db engine: [Date]
If practical, rename the field to avoid similar problems in the future.
And as Gord pointed out, you must also bracket table names which include a space. The same applies to field names.
Still getting problems when using this method of calling the values or dates from the form to be used on the UNION statement. Here is the actual query that I am trying to use.
I don't want to recreate the wheel but I was thinking that if the Date() can be used with between Date() and Date()-6 to represent a 7 days range then I might have to right a module that takes the values from the for and then returns the values that way I can do something like Sdate() and Edate() then this can be used with Between Sdate() and Edate().
I have not tried this yet but this can be my last option I don't even know if it will work but it is worth a try. But before i do that i want to try all the resources that Access can help me make my life easy such as its OO Stuff it has for helping DB programmers.
SELECT
"Expenditure" as [TransactionType], *
FROM
Expenditures
WHERE
(((Expenditures.DateofExpe) Between [Forms]!Form1![Text0] and [Forms]![Form1]![Text11]))
UNION
SELECT
"Income" as [TransactionType], *
FROM
Income
WHERE
(((Income.DateofIncom) Between [Forms]!Form1![Text0] and [Forms]![Form1]![Text11] ));
Access VBA has great power but I don't want to use it as of yet as it will be hard to modify changes for a user that does not know how to program. trying to keep this DB app simple as possible for a dumb user to fully operate.
Any comments is much appreciated.
I want to produce sql like:
select id, "file_name.png" from prefix_table;
In CI, by using active records, I code that with:
$this->db->select('id, "file_name.png"', FALSE)->from('prefix_table');
but what I got is:
select id, prefix_"file_name.png" from prefix_table;
Is there any way to use the table prefix optional? Or may be, how do I do not use the prefix when selecting using active records?
This is a limitation/bug in CodeIgniter right now -- you won't be able to use a string like that without the prefix butting in. I'd suggest writing the query manually. I've opened an issue on Github for it.
Also, you should use an AS column definition when selecting a string like that, otherwise the string name will also be the column name, and you'll end up with something like:
array(
'id' => 2,
'file_name.png' => 'file_name.png'
)
I am developing a PHP script and I have a table like this:
TABLE_CODE
code varchar 8
name varchar 30
this code column has to be a code using random letters from A to Z and characters from 0 to 9 and has to be unique. all uppercase. Something like
A4RTX33Z
I have create a method to generate this code using PHP. But this is a intensive task because I have to query the database to see if the generated code is unique before proceeding and the table may have a lot of records.
Because I know mySQL is a bag of tricks but not having advanced knowledge about it now, I wonder if there's some mechanism that could be built in a table to run a script (or something) every time a new record in created on that table to fill the code column with a unique value.
thanks
edit: What I wonder is if there's a way to created the code on-the-fly, as the record is being added to the table and that code being unique.
Better generate these codes in SQL. This is 8-character random "Promo code generator":
INSERT IGNORE INTO
TABLE_CODE(name, code)
VALUES(
UPPER(SUBSTRING(MD5(RAND()) FROM 1 FOR 8)), -- random 8 characters fixed length
'your code name'
)
Add UNIQUE on code field as #JW suggested, and some error-handling in PHP, because sometimes generated value may be not UNIQUE, and MySQL will raise error in that situation.
Adding a UNIQUE constraint on the code column is the first thing you would need to do. Then, to insert the code I would write a small loop like this:
// INSERT IGNORE will not generate an error if the code already exists
// rather, the affected rows will be 0.
$stmt = $db->prepare('INSERT IGNORE INTO table_code (code, name) VALUES (?, ?)');
$name = 'whatever name';
do {
$code = func_to_generate_code();
$stmt->execute(array($code, $name));
} while (!$stmt->rowCount()); // repeat until at least one row affected
As the table grows the number of loops may increase, so if you feel it should only try three times, you could add it as a loop condition and throw an error if that happens.
Btw, I would suggest using transactions to make sure if an error occurs after the code generation, rolling back will make sure the code is removed (can be reused).