As a part of reporting I want to get some values from database.
Also I included filtering in report UI, like :
select * from invoice where id in (92)
So I am making the postgres statement dynamically(here 92 is the value getting from UI and assigning dynamically). But I want to return all data without any condition if the user select no option, id in this case (no filtering). So how can I handle the "in" clause to return all data without any filtering in this case.
I am asking for a common term that can be included in 'in' clause, so it retun all rows without filtering.
Thanks!
One method is using logic like:
where (v_id is null) or (id = v_id)
Note: be careful about the use of in. It probably will not do what you intend if you expect multiple values to match.
Related
I am new to SQL and POSTGRES and had a quick question. Right now I have 2 different tables one with car info and one with partial car info and I would like to sort on car.vin OR partial_car.vin depending if either exists and sending all nulls/empty strings to the end of the sort. Currently my ORDER BY statement looks like:
ORDER BY nullif(coalesce(car.vin, partial_car.partial_vin), '') asc nulls last limit 50 offset 0
My expectation for this is that coalesce will take the first non null value and use that for sorting or it will return null and send that to the end. My results so far I haven't been able to make sense of. There are null values being placed in between actual values etc.. If I make this change coalesce(car.vin, '') again I see it work properly. Anyone have an ideas as to why this is the behavior? Let me know if you need something more from me.
It was human error on my end. The object being sent to client was not being populated properly with partial data. So sorting was correct but was seeing blanks due to those values not being present.
I am trying this query:
List<Account> onlyRRCustomer = [SELECT
ac.rr_First_Name__c,
ac.rr_Last_Name__c,
ac.rr_National_Insurance_Number__c,
ac.id,
ac.rr_Date_of_Birth__c
FROM
Account ac
WHERE
ac.rr_National_Insurance_Number__c IN :uniqueNiInputSet
AND RecordTypeId = :recordTypeId];
It gives me an error:
SELECT ac.rr_First_Name__c, ac.rr_Last_Name__c,
ac.rr_National_Insurance_Number__c, ac.id, ac.rr_Date_of_Birth__c FROM
Account ac WHERE (ac.rr_National_Insurance_Number__c = :tmpVar1 AND
RecordTypeId = :tmpVar2) 10:12:05.0
(11489528)|EXCEPTION_THROWN|[49]|System.QueryException: Non-selective
query against large object type (more than 200000 rows). Consider an
indexed filter or contact salesforce.com about custom indexing.
I understand uniqueNiInputSet.size() ~ 50, so, it's not an issue but for that record type, it might contains more records.
So, if i changed the position will that work? Means, first the recordtype and then the NIset in where clause. Is there any order how where clause are selected in SF. So, it will only look for 50 member and then within 50 it will serach for the particular record type?
That just means that the script is taking too long to execute. You may need to move this to a #future method or make execute it using Database.Batchable.
I don't think the order matters in SOQL, I think it's just trying to return too many records.
A non-selective query means you are performing a query against a table that has a large number of records and your query is not specific enough. You can work with Salesforce support to try to resolve this, either through the creation of additional backend indexes or by making the query more selective.
To be honest, your query looks very selective already, you're not using LIKE or IN. You should also put your most selective conditions first (resulting in a more focused query against your records).
I know it should'nt matter, but I would also move your conditions out of the parenthesis.
If there are any other fields you can filter on, that may help. Sometimes, you have to actually create new fields and populate them just to help make your queries more selective.
Also, if rr_National_Insurance_Number__c is a formula field, you will want to change it to a text field and populate workflow or apex instead. Formula fields require additional time on the servers to calculate.
SELECT rr_First_Name__c, rr_Last_Name__c, rr_National_Insurance_Number__c, id, rr_Date_of_Birth__c
FROM Account
WHERE new_custom_field__c = TRUE
AND rr_National_Insurance_Number__c = :tmpVar1
AND RecordTypeId = :tmpVar2
Your query is non-selective. For a standard indexes is 30% for the fist million records and 15% of records over a million up to 1 million records total. For and "AND" query each individual where criteria must itself be selective see this quick reference cheat sheet. In general try making
rr_National_Insurance_Number__c
an external id which will make it an indexed by salesforce by default and retry you query. Record Types are already indexed by default. If the result is still non-selective because of the number of results returned, try limiting the number of results using a field like CreatedDate to limit the scope of the query.
I want to do something like this in OrmLite
SELECT *, COUNT(title) as titleCount from table1 group by title;
Is there any way to do this via QueryBuilder without the need for queryRaw?
The documentation states that the use of COUNT() and the like necessitates the use of selectRaw(). I hoped for a way around this - not having to write my SQL as strings is the main reason I chose to use ORMLite.
http://ormlite.com/docs/query-builder
selectRaw(String... columns):
Add raw columns or aggregate functions
(COUNT, MAX, ...) to the query. This will turn the query into
something only suitable for using as a raw query. This can be called
multiple times to add more columns to select. See section Issuing Raw
Queries.
Further information on the use of selectRaw() as I was attempting much the same thing:
Documentation states that if you use selectRaw() it will "turn the query into" one that is supposed to be called by queryRaw().
What it does not explain is that normally while multiple calls to selectColumns() or selectRaw() are valid (if you exclusively use one or the other),
use of selectRaw() after selectColumns() has a 'hidden' side-effect of wiping out any selectColumns() you called previously.
I believe that the ORMLite documentation for selectRaw() would be improved by a note that its use is not intended to be mixed with selectColumns().
QueryBuilder<EmailMessage, String> qb = emailDao.queryBuilder();
qb.selectColumns("emailAddress"); // This column is not selected due to later use of selectRaw()!
qb.selectRaw("COUNT (emailAddress)");
ORMLite examples are not as plentiful as I'd like, so here is a complete example of something that works:
QueryBuilder<EmailMessage, String> qb = emailDao.queryBuilder();
qb.selectRaw("emailAddress"); // This can also be done with a single call to selectRaw()
qb.selectRaw("COUNT (emailAddress)");
qb.groupBy("emailAddress");
GenericRawResults<String[]> rawResults = qb.queryRaw(); // Returns results with two columns
Is there any way to do this via QueryBuilder without the need for queryRaw(...)?
The short answer is no because ORMLite wouldn't know what to do with the extra count value. If you had a Table1 entity with a DAO definition, what field would the COUNT(title) go into? Raw queries give you the power to select various fields but then you need to process the results.
With the code right now (v5.1), you can define a custom RawRowMapper and then use the dao.getRawRowMapper() method to process the results for Table1 and tack on the titleCount field by hand.
I've got an idea how to accomplish this in a better way in ORMLite. I'll look into it.
I am using the fatfree framework, and on the front-end I am using jQuery datatables plugin with server-side processing. And thus, my server-side controller may or may not receive a variable number of information, for example a variable number of columns to sort on, a variable number of filtering options and so forth. So if I don't receive any request for sorting, I don't need to have a ORDER BY portion in my query. So I want to generate the query string in parts as per certain conditions and join it at the end to get the final query for execution. But if I do it this way, I won't have any data sanitization which is really bad.
Is there a way I can use the frameworks internal sanitization methods to build the query string in parts? Also is there a better/safer way to do this than how I am approaching it?
Just use parameterized queries. They are here to prevent SQL injection.
Two possible syntaxes are allowed:
with question mark placeholders:
$db->exec('SELECT * FROM mytable WHERE username=? AND category=?',
array(1=>'John',2=>34));
with named placeholders:
$db->exec('SELECT * FROM mytable WHERE username=:name AND category=:cat',
array(':name'=>'John',':cat'=>34));
EDIT:
The parameters are here to filter the field values, not the column names, so to answer more specifically to your question:
you must pass filtering values through parameters to avoid SQL injection
you can check if column names are valid by testing them against an array
Here's a quick example:
$columns=array('category','age','weight');//columns available for filtering/sorting
$sql='SELECT * FROM mytable';
$params=array();
//filtering
$ctr=0;
if (isset($_GET['filter']) && is_array($_GET['filter'])
foreach($_GET['filter'] as $col=>$val)
if (in_array($col,$columns,TRUE)) {//test for column name validity
$sql.=($ctr?' AND ':' WHERE ')."$col=?";
$params[$ctr+1]=$val;
$ctr++;
}
//sorting
$ctr=0;
if (isset($_GET['sort']) && is_array($_GET['sort'])
foreach($_GET['sort'] as $col=>$asc)
if (in_array($col,$columns,TRUE)) {//test for column name validity
$sql.=($ctr?',':' ORDER BY ')."$col ".($asc?'ASC':'DESC');
$ctr++;
}
//execution
$db->exec($sql,$params);
NB: if column names contain weird characters or spaces, they must be quoted: $db->quote($col)
I have a SELECT query that yields multiple results and do not have any ORDER BY clause.
If I execute this query multiple times and then iterate through results using DataReader.NextResult(), would I be guaranteed to get the results in the same order?
For e.g. if I execute the following query that return 199 rows:
SELECT * FROM products WHERE productid < 200
would I always get the first result with productid = 1 and so on?
As far as I have observed it always return the results in same order, but I cannot find any documentation for this behavior.
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As per my research:
Check out this blog Conor vs. SQL. I actually wanted to ask if the query-result changes even if the data in table remains the same (i.e no update or delete). But it seems like in case of large table, when SQL server employees parallelism, the order can be different
First of all, to iterate the rows in a DataReader, you should call Read, not NextResult.
Calling NextResult will move to the next result set if your query has multiple SELECT statements.
To answer your question, you must not rely on this.
A query without an ORDER BY clause will return rows in SQL Server's default iteration order.
For small tables, this will usually be the order in which the rows were added, but this is not guaranteed and is liable to change at any time. For example, if the table is indexed or partitioned, the order will be different.
No, DataReader will return the results in the order they come back from SQL. If you don't specify an ORDER BY clause, that will be the order that they exist in the table.
It is possible, perhaps even likely that they will always return in the same order, but this isn't guaranteed. The order is determined by the queryplan (at least in SQL Server) on the database server. If something changes that queryplan, the order could change. You should always use ORDER BY if the order of results is in anyway important to your processing of the data.