大约有 30,000 项符合查询结果（耗时：0.0450秒） [XML]
CROSS JOIN vs INNER JOIN in SQL
... but not vs CROSS JOIN. Intersection rows are in JOIN, left/right rows are extra (null-extended) rows in LEFT/RIGHT JOIN. It includes CROSS JOIN as a special case of (INNER) JOIN where there are no rows in the non-intersection.
– philipxy
Nov 29 '15 at 0:39
...
Should MySQL have its timezone set to UTC?
...MySQL datetime fields and daylight savings time -- how do I reference the "extra" hour?
Converting negative values from FROM_UNIXTIME
Sources:
https://bugs.mysql.com/bug.php?id=68861
http://dev.mysql.com/doc/refman/5.0/en/date-and-time-functions.html
http://dev.mysql.com/doc/refman/5.1/en/dateti...
How do you get a list of the names of all files present in a directory in Node.js?
...s was the best solution for me as i wanted to specify filetype easier than string comparisons. Thanks.
– Pogrindis
Oct 26 '14 at 20:09
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html tables: thead vs th
... I didn't even know that th gets bolded by default, without extra CSS, thanks for that!
– CPHPython
Aug 10 '16 at 16:39
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sho...
How to deal with page breaks when printing a large HTML table
...nge it to page-break-after:auto.
It will break correctly and not create an extra blank page.
<html>
<head>
<style>
@media print
{
table { page-break-after:auto }
tr { page-break-inside:avoid; page-break-after:auto }
td { page-break-inside:avoid; page-break-after:auto }...
How do I remove the old history from a git repository?
...ow this is almost the same aswer as @yoyodin, but there are some important extra commands and informations here. I tried to edit the answer, but since it is a substantial change to @yoyodin's answer, my edit was rejected, so here's the information!
...
Why should the “PIMPL” idiom be used? [duplicate]
...
@Rob, I'm guessing there very little overhead to this. An extra class, but there is very little to them. Just a thin wrapper around the existing class. Someone correct me if I'm wrong, but the memory usage would just be an extra function table in RAM, a pointer to the pimpl and a re...
When to Redis? When to MongoDB? [closed]
...lets you give it a key and look up a single value. Redis itself can store strings, lists, hashes, and a few other things; however, it only looks up by name.
Cache invalidation is one of computer science's hard problems; the other is naming things. That means you'll use Redis when you want to avoi...
How to unit test an object with database queries
...a, but applies to all OO-languages)
class Database {
public Result query(String query) {... real db here ...}
}
class MockDatabase extends Database {
public Result query(String query) {
return "mock result";
}
}
class ObjectThatUsesDB {
public ObjectThatUsesDB(Database db) {
this....
SQL Switch/Case in 'where' clause
... @selectedValue varchar (50)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
SELECT
drugstock_drugname.n_cur_bal,drugname.cdrugname,clinic.cclinicname
FROM drugstock_drugname
INNER JOIN drugname ON drugstock_drugname.dr...