null Questions
39
Solved
What is the difference between null and undefined in JavaScript?
Broadcloth asked 22/2, 2011 at 10:30
22
Solved
TypeScript, --strictNullChecks mode.
Suppose I have an array of nullable strings (string | null)[]. What would be a single-expression way to remove all nulls in a such a way that the result has typ...
Build asked 30/3, 2017 at 13:2
2
Solved
In pyspark, I have a dataframe that has dates that get imported as strings. There are null values in these dates-as-strings columns. I'm trying to convert these columns into date type columns, but ...
Papyraceous asked 24/4, 2017 at 18:23
6
Solved
I'd like to perform division in a SELECT clause. When I join some tables and use aggregate function I often have either null or zero values as the dividers. As for now I only come up with this meth...
Heterotopia asked 16/7, 2013 at 15:56
10
When I execute update-database command, it shows this error message
System.ArgumentNullException: Value cannot be null.
Parameter name: type
at System.Activator.CreateInstance(Type type, B...
Supertonic asked 21/1, 2017 at 9:13
10
Solved
How do you replace a NULL value in the select with an empty string?
It doesn't look very professional to output "NULL" values.
This is very unusual and based on my syntax I would expect i...
8
I've wrote a query to check for users with certain criteria, one being they have an email address.
Our site will allow a user to have or not have an email address.
$aUsers=$this->readToArray('...
9
Solved
I am looking for the best way to check if a Com Object exists.
Here is the code that I have; I'd like to improve the last line:
$ie = New-Object -ComObject InternetExplorer.Application
$ie.Naviga...
Alcoholometer asked 13/12, 2010 at 14:56
3
Solved
I have a CSV file with some integer column, now it 's saved as "" (empty string).
I want to COPY them to a table as NULL value.
With JAVA code, I have try these:
String sql = "COPY " + tableName...
Postexilian asked 26/8, 2017 at 6:4
11
Solved
Let's say I'd like to perform the following command:
house.getFloor(0).getWall(WEST).getDoor().getDoorknob();
To avoid a NullPointerException, I'd have to do the following if:
if (house != null...
Nkrumah asked 11/8, 2010 at 12:55
2
Solved
This is one strange, unwanted behavior I encountered in Postgres:
When I create a Postgres table with composite primary keys, it enforces NOT NULL constraint on each column of the composite combina...
Photomural asked 30/10, 2014 at 0:5
4
Solved
I'm having a problem with some SQL queries that I cant figure out.
SELECT * FROM MasterList WHERE Requested <> "Yes";
If I run the above query on my table I get 60 records returned. Howeve...
6
Are these equivalent:
if (null==myobject)
{
//do something
}
and
if (myobject==null)
{
//do something
}
or will they produce different code?
8
Solved
I have made a small xslt file to create an html output called weather.xsl with code as follows:
<!-- DWXMLSource="http://weather.yahooapis.com/forecastrss?w=38325&u=c" -->
<xsl:styles...
Brendon asked 10/12, 2011 at 12:36
7
Solved
Sometimes developers checks if Strings are null values, if yes, sets those Strings as empty value:
if (text == null) {
text = "";
}
What I want to do is to write opposite if statement:
if (tex...
Marchall asked 30/1, 2019 at 14:42
24
Solved
How can I check for null values in JavaScript? I wrote the code below but it didn't work.
if (pass == null || cpass == null || email == null || cemail == null || user == null) {
alert("fill a...
Torrietorrin asked 14/5, 2011 at 18:15
13
Solved
While looking through some old code I came across this gem:
MyObject o = new MyObject("parameter");
if (o == null) o = new MyObject("fallback parameter");
The second line is marked in Eclipse as...
Covell asked 19/6, 2012 at 14:44
6
Solved
I try to insert the value null (DateTime) in my database for a field typed 'date' but I always get a '0001-01-01'. I don't understand, this field "allow nulls" and I don't know why I have this defa...
Jarlen asked 22/5, 2013 at 13:8
9
Solved
According to §6.3.2.3 ¶3 of the C11 standard, a null pointer constant in C can be defined by an implementation as either the integer constant expression 0 or such an expression cast to void *. In C...
Allseed asked 21/12, 2022 at 3:42
8
Solved
I have a Join
SELECT * FROM Y
INNER JOIN X ON ISNULL(X.QID, 0) = ISNULL(y.QID, 0)
Isnull in a Join like this makes it slow. It's like having a conditional Join.
Is there any work around to som...
Tsarevna asked 4/2, 2010 at 18:32
2
I want to map nested java objects. Customer.address.houseNumber to userDTO.homeDTO.addressDTO.houseNo.
Expectation: If and only if Customer.address.houseNumber is not null, then create homeDTO obje...
6
Solved
select distinct "column" from table;
output:
column
1 0.0
2 [null]
3 1.0
But when I try to count the null values
select count("column") from train where "column" is NULL;
Gives output 0 (z...
Litho asked 26/12, 2018 at 16:1
9
Solved
If I have the table
SELECT (Firstname || '-' || Middlename || '-' || Surname) AS example_column
FROM example_table
This will display Firstname-Middlename-Surname e.g.
John--Smith
Jane-Anne-Sm...
Sesterce asked 19/5, 2016 at 17:30
11
Solved
I'm using this code and I'm beyond frustration:
try {
$dbh = new PDO('mysql:dbname=' . DB . ';host=' . HOST, USER, PASS);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbh-...
Jelena asked 8/9, 2009 at 3:14
5
Is there a way to remove the columns of a spark dataFrame that contain only null values ?
(I am using scala and Spark 1.6.2)
At the moment I am doing this:
var validCols: List[String] = List()
fo...
Immunity asked 11/9, 2016 at 13:32
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