mySQL NOOB question:
Table has a column = AgeGroup. It is populated with the following data options: U40, 40-44, 45-49, 50-54, 55-59, 60+.
I have a form which allows the user to select the 'Gender' and 'AgeGroup' they wish to view. This then uses a "WHERE" clause of "SELECT" SQL query. It uses in the following format:
FROM
#__test1
WHERE
EventName = '2011EoSummer' AND
Gender = {$REQUEST:Gender};
if(isset($_REQUEST['Age'])) AND AgeGroup = {$_REQUEST['Age']}
In the form, there is a option to get all ages via "Overall" but there is no data called "Overall" in the AgeGroup column. Overall should default to ALL age groups, but I don't know how this would read in the SQL query.
Example 1 URL: /&Gender=Men&AgeGroup=U40 => would display data in 'U40' 'Men'
Example 2 URL: /&Gender=Men&Age=Overall => would display ALL Age data
If I'm reading this right, when you have "overall" selected you want to return all the age groups (so as not to limit by any age group)?
If so you need to remove the AgeGroup clause in your SQL statment.
<?PHP
$sql = "SELECT * FROM tbl WHERE Gender = {$_REQUEST['gender']}";
if(isset($_REQUEST['age']))
{
$sql.= " AND AgeGroup = {$_REQUEST['age']}"
}
?>
This will default to overall, so you may want to change the logic appropriately, hope I got what you were after, if not ignore it!
Also as a side note $_REQUEST isn't the best to use, if your using a form as your action collector set it to post and use $_POST instead, if you cant use $_GET to pull your data out of the url instead of request.
Edit: Added in brackets to make it easier to read.
Related
Let me preface by saying I'm very new to SQL (and back end design) in general. So for those annoyed with noob questions, please be gentle.
BACKGROUND:
I'm trying to build a product test database (storing test data for all our products) where I want a user to be able to refine a search to find test data they actually want. For example, they may start by searching for all products of a certain brand name, and then refine it with a product type, and/or refine it with a date range of when the test was done.
PROBLEM:
I'm having a hard time finding information on how to implement multi-parameter searches with mysql and node.js. I know you can do nested queries and joins and such within pure SQL syntax, but it's not abundantly clear to me how I would do this from node.js, especially when certain search criteria aren't guaranteed to be used.
Ex:
CREATE PROCEDURE `procedureName`(
IN brandname VARCHAR(20),
producttype VARCHAR(30))
BEGIN
SELECT * FROM products
WHERE brand = brandname
AND product_type = producttype;
END
I know how to pass data from node.js to this procedure, but what if the user didn't specify a product type? Is there a way to nullify this part of the query? Something like:
AND product_type = ALL;
WHAT I'VE TRIED:
I've also looked into nesting multiple SQL procedures, but passing in dynamic data to the "FROM" clause doesn't seem to be possible. Ex: if I had a brandname procedure, and a product type procedure, I don't know how/if I can pass the results from one procedure to the "FROM" clause of the other to actually refine the search.
One idea was to create tables with the results in each of these procedures, and pass those new table names to subsequent procedures, but that strikes me as an inefficient way to do this (Am I wrong? Is this a completely legit way to do this?).
I'm also looking into building a query string on the node side that would intelligently decide what search criteria have been specified by the front end, and figure out where to put SQL AND's and JOIN's and what-nots. The example below actually works, but this seems like it could get ugly quick as I add more search criteria, along with JOINS to other tables.
// Build a SQL query based on the parameters in a request URL
// Example request URL: http://localhost:3000/search?brand=brandName&type=productType
function qParams(req) {
let q = "SELECT * FROM products WHERE ";
let insert = [];
if(req.query.brand) {
brandname = req.query.brand; // get brandname from url request
q = q + `brand = ?`, // Build brandname part of WHERE clause
insert.push(brandname); // Add brandname to insert array to be used with query.
};
if(req.query.type) {
productType = req.query.type; // get product type from url request
insert.length > 0 ? q = q + ' AND ' : q = q; // Decide if this is the first search criteria, add AND if not.
q = q + 'product_type = ?'; // Add product_type to WHERE clause
insert.push(productType); // Add product_type variable to insert array.
}
// Return query string and variable insert array
return {
q: q,
insert: insert
};
};
// Send Query
async function qSend(req, res) {
const results = await qParams(req); // Call above function, wait for results
// Send query string and variables to MySQL, send response to browser.
con.query(results.q, results.insert, (err, rows) => {
if(err) throw err;
res.send(rows);
res.end;
})
};
// Handle GET request
router.use('/search', qSend);
CONCISE QUESTIONS:
Can I build 1 SQL procedure with all my search criteria as variables, and nullify those variables from node.js if certain criteria aren't used?
Is there way to nest multiple MySQL procedures so I can pick the procedures applicable to the search criteria?
Is creating tables of results in a procedure, and passing those new table names to other procedures a reasonable way to do that?
Building the query from scratch in node is working, but it seems bloated. Is there a better way to do this?
Googling "multi-parameter search mysql nodejs" is not producing useful results for my question, i.e. I'm not asking the right question. What is the right question? What do I need to be researching?
One option is to use coalesce():
SELECT p.*
FROM products p
WHERE
p.brand = COALESCE(:brandname, p.brand)
AND p.product_type = COALESCE(:producttype, p.producttype);
It may be more efficient do explicit null checks on the parameters:
SELECT p.*
FROM products p
WHERE
(:brandname IS NULL OR p.brand = :brandname)
AND (:producttype IS NULL OR p.product_type = :producttype);
I have no problem with selecting a model tagged with certain tag
$lis = Capacitytype::find(124)->entities()->orderBy('name','asc')->get();
In my Capacitytype model I have this relation:
public function entities()
{
return $this->belongsToMany('App\Models\Entity', 'entity_capacitytypes', 'capacitytype_id', 'entity_id');
}
MY PROBLEM:
I wish to use the same selection f models to fill a select field in a form. (I use select2.js)
When I try to implement this code
$lis = array(null => 'Commitee') + Capacitytype::find(124)->entities()->orderBy('name','asc')->lists('name', 'id')->all();
I get this error:
SQLSTATE[23000]: Integrity constraint violation: 1052 Column 'id' in field list is ambiguous (SQL: select name, id from entities inner join entity_capacitytypes on entities.id = entity_capacitytypes.entity_id where entities.deleted_at is null and entity_capacitytypes.capacitytype_id = 6 order by name asc)
I tried to solve this issue by adding table name to my code, but this is as far as I was able to go:
->lists('entities.name', 'entities.id')
My Question:
how modify the code to get the desired collection for my select field?
Thank you.
You could make use of Laravel's with() to perform an eager loading as a workaround for this issue. To do so, just pass the name of the relation (i.e. entities) to the method:
Capacitytype::find(124)->with('entities')->orderBy('name','asc')->lists('entities.name', 'entities.id');
Or else, you could first fetch the records, and then reformat it to match your usecase:
$list = Capacitytype::find(124)->entities()->orderBy('name','asc')->get()->toArray();
As such, you can refine the returned list of arrays, to match your id => name format (hence, a substitute for the lists method).
$refinedList = array();
foreach($list as $entity){
$refinedList[$entity['id']] = $entity['name'];
}
And, there you go.
My database (mysql) tables use TIMESTAMP columns, and whenever I want them returned in a query, I want them to be queried as "UNIX_TIMESTAMP(columnname)".
How do you easily modify queries in zend framework to achieve this?
For example, the current code is:
select = $this->select();
$select->where('user_id = ?',$user_id);
return $this->fetchAll($select);
This eventually becomes:
select * from tablename where user_id = 42;
I want something that automatically finds the TIMESTAMP column and changes the resulting query to:
select user_id,name,unix_timestamp(created) where user_id = 42;
I know I can use a MySQL view to achieve this, but I'd rather avoid that.
Thanks.
RR
You should be able to specify the fields you want in the select using the $select->from() object.
Zend_Db_Select
You should end up with something like this.
$select = $this->select();
$select->from(
array('t' => 'tablename'),
array('user_id', 'name', 'UNIX_TIMESTAMP(created)')
);
$select->where('user_id = ?',$user_id);
return $this->fetchAll($select);
If you wanted to run an expression that doesn't have parenthese in the function, Use the Zend_Db_Expr() method to escape the query properly.
So I use the PDO for a DB connection like this:
$this->dsn[$key] = array('mysql:host=' . $creds['SRVR'] . ';dbname=' . $db, $creds['USER'], $creds['PWD']);
$this->db[$key] = new PDO($this->dsn[$key]);
Using PDO I can then execute a MySQL SELECT using something like this:
$sql = "SELECT * FROM table WHERE id = ?";
$st = $db->prepare($sql);
$st->execute($id);
$result = $st->fetchAll();
The $result variable will then return an array of arrays where each row is given a incremental key - the first row having the array key 0. And then that data will have an array the DB data like this:
$result (array(2)
[0]=>[0=>1, "id"=>1, 1=>"stuff", "field1"=>"stuff", 2=>"more stuff", "field2"=>"more stuff" ...],
[1]=>[0=>2, "id"=>2, 1=>"yet more stuff", "field1"=>"yet more stuff", 2=>"even more stuff", "field2"=>"even more stuff"]);
In this example the DB table's field names would be id, field1 and field2. And the result allows you to spin through the array of data rows and then access the data using either a index (0, 1, 2) or the field name ("id", "field1", "field2"). Most of the time I prefer to access the data via the field names but access via both means is useful.
So I'm learning the ruby-mysql gem right now and I can retrieve the data from the DB. However, I cannot get the field names. I could probably extract it from the SQL statement given but that requires a fair bit of coding for error trapping and only works so long as I'm not using SELECT * FROM ... as my SELECT statement.
So I'm using a table full of State names and their abbreviations for my testing. When I use "SELECT State, Abbr FROM states" with the following code
st = #db.prepare(sql)
if empty(where)
st.execute()
else
st.execute(where)
end
rows = []
while row = st.fetch do
rows << row
end
st.close
return rows
I get a result like this:
[["Alabama", "AL"], ["Alaska", "AK"], ...]
And I'm wanting a result like this:
[[0=>"Alabama", "State"=>"Alabama", 1=>"AL", "Abbr"=>"AL"], ...]
I'm guessing I don't have the way inspect would display it quite right but I'm hoping you get the idea by now.
Anyway to do this? I've seen some reference to doing this type of thing but it appears to require the DBI module. I guess that isn't the end of the world but is that the only way? Or can I do it with ruby-mysql alone?
I've been digging into all the methods I can find without success. Hopefully you guys can help.
Thanks
Gabe
You can do this yourself without too much effort:
expanded_rows = rows.map do |r|
{ 0 => r[0], 'State' => r[0], 1 => r[1], 'Abbr' => r[1] }
end
Or a more general approach that you could wrap up in a method:
columns = ['State', 'Abbr']
expanded_rows = rows.map do |r|
0.upto(names.length - 1).each_with_object({}) do |i, h|
h[names[i]] = h[i] = r[i]
end
end
So you could collect up the rows as you are now and then pump that array of arrays through something like what's above and you should get the sort of data structure you're looking for out the other side.
There are other methods on the row you get from st.fetch as well:
http://rubydoc.info/gems/mysql/2.8.1/Mysql/Result
But you'll have to experiment a little to see what exactly they return as the documentation is, um, a little thin.
You should be able to get the column names out of row or st:
http://rubydoc.info/gems/mysql/2.8.1/Mysql/Stmt
but again, you'll have to experiment to figure out the API. Sorry, I don't have anything set up to play around with the MySQL API that you're using so I can't be more specific.
I realize that php programmers are all cowboys who think using a db layer is cheating, but you should really consider activerecord.
User Form Input - City
User Form Input - Venue
User Form Input - Cover
User Form Input - Time
User Form Input - Date
User Form Input - Number1
User Form Input - Number2
(if any are blank they are coverted to '*' on the way in. But could be whatever works.)
my $grabgig = $hookup->prepare(qq{SELECT `VenueNumber`,`Venue`,`CoverCharge`,`SetLength`,`City`,`Owner`,`Date`,`Time`,`Image1`,`Number`
FROM `gigs`
WHERE VenueNumber > ? AND `City` = ? AND `Venue` = ? AND `CoverCharge` = ?
AND Date = ? AND `Number` > ? AND `Number` < ?
AND `Time` LIKE ? LIMIT ?,?});
##########################################
$grabgig->execute('100',$city,$venue,$cover,'*',$number1,$number2,?,'0','6')
or die "Did not execute";
That is a basic example above.
I want to be able to return results based on the City Input.
If more input is present, then narrow down results accordingly.
But the query returns nothing if fields are empty (*).
I tried wildcards and so on then, I experimented with LIKE and NOT LIKE.
This seemingly simple search is driving me nuts.
Can someone help this newbie?
OK, I'm pretty unsure what you mean, BUT, my best undererstanding of what you're trying to do is to query like you do now BUT if a particular field is not populated in the form, to avoid adding that field to the where clause; as opposed to current query which instead does and myField="*".
Correct?
If that's so, you need to build your query, and replacement list, in pieces:
my $sql = qq{SELECT MY_FIELD_LIST_TOO_LAZY_TO_TYPE FROM `gigs` WHERE 2=2};
my #replacement_values = (); # These go into execute() instead of "?"s
if ($city ne "*") {
$sql .= qq[AND city = ?];
push #replacement_values, $city;
}
if ($number1 ne "*") {
$sql .= qq[AND number > ?];
push #replacement_values, $number1;
}
# ... more values processed the same way
my $grabgig = $hookup->prepare($sql);
$grabgig->execute(#replacement_values) or die "Did not execute";
If you want to do it more intelligently (i.e. to generalize), you will have the form fields in a hash; have a config hash mapping the form field name to the DB column name and the operator, and instead do the above as:
my %fields = (
city => ["city" , "="]
,number1 => ["number", ">"]
,number2 => ["number", "<"]
);
my $sql = qq{SELECT MY_FIELD_LIST_TOO_LAZY_TO_TYPE FROM `gigs` WHERE 2=2};
my #replacement_values = (); # These go into execute() instead of "?"s
foreach my $field (keys %form_data) {
next unless exists $fields{$field};
if ($form_data{$field} ne "*") {
$sql .= qq[ AND $fields{$field}->[0] $fields{$field}->[1] ?];
push #replacement_values, $form_data{$field};
}
}
my $grabgig = $hookup->prepare($sql);
$grabgig->execute(#replacement_values) or die "Did not execute";
I am assuming that you want to construct a query where only a few input parameters have valid values and the rest are undefined. If that is indeed what you want, here is what you could do: Construct the query dynamically. Here are the steps you could take assuming you are using CGI.pm and assuming that the where clause is just a series of "this = that" - In your case you have different operators - but the idea is the same.
First construct a "where" string from the CGI query parameter (Sorry untested code):
my $qrystr = '';
foreach ($query->param) {
if (my $val = $query->param($_)) {
$qrystr .= "where $_ = " . $dbh->quote($val) . ' and ';
}
}
$qrystr .= "where 1 = 1";
Now you can just prepare and execute the query : "select * from table $qrystr"
If you want automatic quoting you will have to use bind parameters which is an easy extension of the code above
Update There was a missing "where" in the last true clause "1 = 1" - Sorry, added it now
Sorry, the formatting bar was not appearing so, I rebooted. Now I cannot edit my question or comment.
What I am trying to do is provide a search for the users.
They select a city from a dropdown then some optional data can be entered / selected to narrow the results.
The optional data May or May Not be present in the table, could be a blank field.
I would like the results to show based on the selected criteria of the search in that City.
So, WHERE selected "input city" = "tables city column" look for the other options (ignore that particular criteria if field is empty) and return any matches that exist for that city.
I am then pushing into array in a While for output display.
I guess it would be like a car query. Select make where doors = 2 and color = red and engine = hamsterwheel but, the color field may be empty in the database..