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typecast string to integer - Postgres
...ur value is an empty string, you can use NULLIF to replace it for a NULL:
SELECT
NULLIF(your_value, '')::int
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How to list all the available keyspaces in Cassandra?
...keyspace in the system schema using the SQL query
below is the command.
SELECT * FROM system_schema.keyspaces;
Hope this will answer your question...
You can go through the explanation on understanding and creating the keyspaces from below resources.
Documentation:
https://docs.datastax.co...
Counting null and non-null values in a single query
...le and SQL Server (you might be able to get it to work on another RDBMS):
select sum(case when a is null then 1 else 0 end) count_nulls
, count(a) count_not_nulls
from us;
Or:
select count(*) - count(a), count(a) from us;
...
How to replace ${} placeholders in a text file?
... occur normally $((...)), `...`, and $(...), though backslash is an escape character here, but you don't have to worry that the parsing has a bug, and it does multiple lines just fine.
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Run a Docker image as a container
...ing
Then list all the containers you have made:
sudo docker ps -a
And select the container you want to work with (mine is 167ddd6d7f15):
sudo docker start -ai 167ddd6d7f15
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Event handler not working on dynamic content [duplicate]
...
You have to add the selector parameter, otherwise the event is directly bound instead of delegated, which only works if the element already exists (so it doesn't work for dynamically loaded content).
See http://api.jquery.com/on/#direct-and-del...
Detect if value is number in MySQL
...
This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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How can I extract embedded fonts from a PDF as valid font files?
...or FontForge:
Use the "Open Font" dialogbox used when opening files.
Then select "Extract from PDF" in the filter section of dialog.
Select the PDF file with the font to be extracted.
A "Pick a font" dialogbox opens -- select here which font to open.
Check the FontForge manual. You may need to fol...
What is your favorite C programming trick? [closed]
.... you could make a string "object" like this:
struct X {
int len;
char str[1];
};
int n = strlen("hello world");
struct X *string = malloc(sizeof(struct X) + n);
strcpy(string->str, "hello world");
string->len = n;
here, we've allocated a structure of type X on the heap that is the...
SQL Server SELECT INTO @variable?
...
You cannot SELECT .. INTO .. a TABLE VARIABLE. The best you can do is create it first, then insert into it. Your 2nd snippet has to be
DECLARE @TempCustomer TABLE
(
CustomerId uniqueidentifier,
FirstName nvarchar(100),
LastNa...