大约有 40,000 项符合查询结果（耗时：0.0792秒） [XML]
How do I cast a string to integer and have 0 in case of error in the cast with PostgreSQL?
...dn't want the overhead of a function. I came up with the following query:
SELECT myfield::integer FROM mytable WHERE myfield ~ E'^\\d+$';
Postgres shortcuts its conditionals, so you shouldn't get any non-integers hitting your ::integer cast. It also handles NULL values (they won't match the regex...
using href links inside tag
...
<select name="forma" onchange="location = this.value;">
<option value="Home.php">Home</option>
<option value="Contact.php">Contact</option>
<option value="Sitemap.php">Sitemap</option>...
Get size of all tables in database
...
SELECT
t.NAME AS TableName,
s.Name AS SchemaName,
p.rows,
SUM(a.total_pages) * 8 AS TotalSpaceKB,
CAST(ROUND(((SUM(a.total_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS TotalSpaceMB,
SUM(a.used_pa...
How do I use ROW_NUMBER()?
...
For the first question, why not just use?
SELECT COUNT(*) FROM myTable
to get the count.
And for the second question, the primary key of the row is what should be used to identify a particular row. Don't try and use the row number for that.
If you returned Ro...
How do I select an entire row which has the largest ID in the table?
...
You could use a subselect:
SELECT row
FROM table
WHERE id=(
SELECT max(id) FROM table
)
Note that if the value of max(id) is not unique, multiple rows are returned.
If you only want one such row, use @MichaelMior's answer,
SELEC...
How do I get the value of text input field using JavaScript?
... 'searchtext' in your page.
Method 5:
Use the powerful document.querySelector('selector').value which uses a CSS selector to select the element
For example, document.querySelector('#searchTxt').value; selected by id
document.querySelector('.searchField').value; selected by class
...
Is there a MySQL command to convert a string to lowercase?
...nction is LOWER() or LCASE() (they both do the same thing).
For example:
select LOWER(keyword) from my_table
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What are named pipes?
...
#include <sys/types.h>
#include <sys/stat.h>
int mkfifo(const char *pathname, mode_t mode);
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Pipe to/from the clipboard in Bash script
...lets you talk to it.
In the case of X, there's xclip (and others). xclip -selection c will send data to the clipboard that works with Ctrl + C, Ctrl + V in most applications.
If you're on Mac OS X, there's pbcopy. e.g cat example.txt | pbcopy
If you're in Linux terminal mode (no X) then look into...
Mac SQLite editor [closed]
... info.plist and setting it to YES
Running the app on a device
Open iTunes
Select the device
Select the "Apps" tab
Scroll down to the "File Sharing" section and select the app
The .sqlite file should appear in the right hand pane - select it and "Save to..."
Once it's saved open it up in your favour...