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'
)
Related
I've created a MySQL sproc which returns 3 separate result sets. I'm implementing the npm mysql package downstream to exec the sproc and get a result structured in json with the 3 result sets. I need the ability to filter the json result sets that are returned based on some type of indicator in each result set. For example, if I wanted to get the result set from the json response which deals specifically with Suppliers then I could use some type of js filter similar to this:
var supplierResultSet = mySqlJsonResults.filter(x => x.ResultType === 'SupplierResults');
I think SQL Server provides the ability to include a hard-coded column value in a SQL result set like this:
select
'SupplierResults',
*
from
supplier
However, this approach appears to be invalid in MySQL b/c MySQL Workbench is telling me that the sproc syntax is invalid and won't let me save the changes. Do you know if something like what I'm trying to achieve is possible in MySQL and if not then can you recommend alternative approaches that would help me achieve my ultimate goal of including some type of fixed indicator in each result set to provide a handle for downstream filtering of the json response?
If I followed you correctly, you just need to prefix * with the table name or alias:
select 'SupplierResults' hardcoded, s.* from supplier s
As far as I know, this is the SQL Standard. select * is valid only when no other expression is added in the selec clause; SQL Server is lax about this, but most other databases follow the standard.
It is also a good idea to assign a name to the column that contains the hardcoded value (I named it hardcoded in the above query).
In MySQL you can simply put the * first:
SELECT *, 'SupplierResults'
FROM supplier
Demo on dbfiddle
To be more specific, in your case, in your query you would need to do this
select
'SupplierResults',
supplier.* -- <-- this
from
supplier
Try this
create table a (f1 int);
insert into a values (1);
select 'xxx', f1, a.* from a;
Basically, if there are other fields in select, prefix '*' with table name or alias
Am trying to Query inside an SQL table which has XML Column .
Table name: 'Purchase'
Column name: 'XML_COL'
Please find below xml data for column name 'XML_COL' under purchase table:
<ns1:Request xmlns:ns1="http://www.sample.com/hic/event/request"
xmlns:ns2="http://www.sample.com/hic/eventpayload/request">
<ns1:createeventRequest>
<ns1:eventPayLoad>
<ns2:eventPayLoad>
<Id>123456</Id>
</ns2:eventPayLoad>
</ns1:eventPayLoad>
</ns1:createeventRequest>
</ns1:Request>
I have written below query :
`select * from purchase,
XMLTABLE ('$d/Request/createeventRequest/eventPayLoad/eventPayLoad' PASSING XML_COL as "d"
COLUMNS
Id varchar(20) PATH 'Id') as a where(a.Id like '1234%');`
But this is returning me an empty column with no data.
But my requirement is it should fetch all the data for this particular Id.
Please help if any one faced this kind of issue.
Do we need to include namespaces as well while querying?? or am I missing any thing?
I think the expression PATH 'Id' is bit to simple...
I'm not familiar with MySQL's abilities to query XML... The Path Id would try to find an element "Id" from the current node (which is the root node in the first action). But there is no "Id"... You must either specify the full path, starting with a single / to start at the root node, or let the engine try a deep search, starting with two //
These paths should work:
SELECT ExtractValue(
'<ns1:Request xmlns:ns1="http://www.sample.com/hic/event/request" xmlns:ns2="http://www.sample.com/hic/eventpayload/request">
<ns1:createeventRequest>
<ns1:eventPayLoad>
<ns2:eventPayLoad>
<Id>123456</Id>
</ns2:eventPayLoad>
</ns1:eventPayLoad>
</ns1:createeventRequest>
</ns1:Request>',
'/ns1:Request[1]/ns1:createeventRequest[1]/ns1:eventPayLoad[1]/ns2:eventPayLoad[1]/Id[1]' ) AS result;
If there is only one element with a value (in your case "Id") you might use the simple deep search like this:
SELECT ExtractValue(
'<ns1:Request xmlns:ns1="http://www.sample.com/hic/event/request" xmlns:ns2="http://www.sample.com/hic/eventpayload/request">
<ns1:createeventRequest>
<ns1:eventPayLoad>
<ns2:eventPayLoad>
<Id>123456</Id>
</ns2:eventPayLoad>
</ns1:eventPayLoad>
</ns1:createeventRequest>
</ns1:Request>',
'//Id[1]' ) AS result;
But - in general - it is good advise to be as specific as possible...
Just cracked the query...When name spaces are being used in an XML, instead of the entire path, I found it's better to use '/*//' which traverses through the required element tag through XML.
Final Query:
select * from purchase,
XMLTABLE('$d' PASSING XML_COL as "d"
COLUMNS
Id varchar(20) PATH '/*//Id') as a where(a.Id like '1234%') with ur
Using 'with ur' helps to read the data that has not been committed in the database.
Please post comments if it is helpful.
I'm totally new in yii2 and I want to know what does it mean the colon in the query?
I have made a research about binding parameters, but in the yii2 documentation says:
// returns all inactive customers
$sql = 'SELECT * FROM customer WHERE status=:status';
which side is from the data base? the left side or the right side?
which is a simple text and which one is a column from the DB? Im so confused.
what would be another way to make the query without the colon? is it valid?
why it has 'anyo = **:**valor' in the next example? and some others dont?
$dbLibro = Libro::find()->where('tipo = "Nacimiento"')->andWhere('cerrado = 0')->andWhere('anyo = :valor',[':valor'=>date("Y")])->one();
I hope its clear cause the documentation is a bit confusing for me.
The colons are not directly related with Yii2, it's related with PHP PDO extension that used by Yii2.
Each colon is placeholder used later for binding value. Check for example this question.
If we write this query in ActiveQuery:
SELECT * FROM customer WHERE status = :status
we can get something like this:
$query = Customer::find()->where('status = :status', [':status' => Customer::STATUS_ACTIVE]);
Assuming STATUS_ACTIVE constant equals to 1, after execution it transforms to this:
SELECT * FROM "customer" WHERE status = 1
So the left side (before equals) represents column name, right part - value which will be safely binded after.
But you don't have to write params by yourself, Yii2 QueryBuilder generates it automatically for you.
There are other ways to write query without colons and they are used more often. This query can be written like this:
$query = Customer::find(['status' => Customer::STATUS_ACTIVE]);
$models = $query->all();
Or like this using shortcut:
$models = Customer::findAll(['status' => Customer::STATUS_ACTIVE]);
Or it can be even put inside of a scope:
$models = Customer::find()->active();
In this case Yii generates parameters automatically and it will be equivalent to this:
SELECT * FROM "customer" WHERE "status"=:qp1
Value 1 will be binded to :qp1 parameter, note that in this case column names are also double quoted.
If you try to use more conditions, params will be :qp2, :qp3 and so on (default PARAM_PREFIX is :qp).
As for your second query, it can be rewritten like this:
$model = Libro::find()
->where([
'tipo' => 'Nacimiento',
'cerrado' => 0,
'anyo' => date('Y'),
])->one();
Such queries look way better and readable in this state.
Yii2 allows generate even more complex conditions in queries, check this section of the docs for more details.
P.S. It's better to use english for naming in your code. Think about other international developers supporting your code. date('Y') can be calculated using database functions depending on used RDBMS.
I am working on a problem where I need to add an OR clause to a set of existing conditions. The current conditions are built in a hash in a method and at the end, they are used in the where clause. Here is a simplified example:
...
conds.merge!({:users => {:archived => false}})
Model.where(conds)
I am trying to add an OR clause to the current set of conditions so it would be something like '(conditions) OR new_condition'. I'd like to add the OR statement without converting each addition to the conds hash into a string. That would be my last option. I was hoping someone has done something like this before (without using Arel). I seem to recall in Rails 2 there was a way to parse a conditions hash using a method from the model (something like Model.some_method(conds) would produce the where clause string. Maybe that would be a good option to just add the OR clause on to that string. Any ideas are appreciated. Thank you for your help!
I found a way to do what I needed. Instead of changing all of the conditions that I am building, I am parsing the conditions to SQL using sanitize_sql_for_conditions. This is a private method in ActiveRecord, so I had to put a method on the model to allow me to access it. Here is my model method:
def self.convert_conditions_hash_to_sql(conditions)
self.sanitize_sql_for_conditions(conditions)
end
So, once I convert my conditions to text, I can add my OR clause (along with the appropriate parentheses) to the end of the original conditions. So, it would go something like this:
Model.where('(?) OR (model.type = ? AND model.id IN(?))', Model.convert_conditions_hash_to_sql(conds), model_type, model_id_array)
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"