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MySQL select 10 random rows from 600K rows fast
How can I best write a query that selects 10 rows randomly from a total of 600k?
26 Answers
...
MySQL query to get column names?
...NFORMATION_SCHEMA`.`COLUMNS`
WHERE `TABLE_SCHEMA`='yourdatabasename'
AND `TABLE_NAME`='yourtablename';
It's VERY powerful, and can give you TONS of information without need to parse text (Such as column type, whether the column is nullable, max column size, character set, etc)...
Oh, and it...
log all sql queries
... '()': 'django.utils.log.RequireDebugTrue',
}
},
'handlers': {
'console': {
'level': 'DEBUG',
'filters': ['require_debug_true'],
'class': 'logging.StreamHandler',
}
},
'loggers': {
'django.db.backends': {
...
What is a void pointer in C++? [duplicate]
...ollowing:
It is dealing in unformatted memory. This is what operator new and malloc return: a pointer to a block of memory of a certain size. Since the memory does not have a type (because it does not have a properly constructed object in it yet), it is typeless. IE: void.
It is an opaque handle; ...
Select elements by attribute in CSS
...L5 feature",
browsers typically don't have any problems supporting non-standard attributes, so you should be able to filter them with attribute selectors; and
you don't have to worry about CSS validation either, as CSS doesn't care about non-namespaced attribute names as long as they don't break t...
Parallel foreach with asynchronous lambda
I would like to handle a collection in parallel, but I'm having trouble implementing it and I'm therefore hoping for some help.
...
Why doesn't “System.out.println” work in Android?
...onsole, so that I can debug it. But for some reason, nothing prints in my Android application.
11 Answers
...
How to clear an ImageView in Android?
...ike, i didn't).
I think the best solution is:
viewToUse.setImageResource(android.R.color.transparent);
I like this solution the most cause there isn't anything tricky in reverting the state and it's also clear what it is doing.
...
Convert array of strings into a string in Java
...arr) {
builder.append(s);
}
String str = builder.toString();
(Java 8 and above):
String str = String.join(",", arr);
And if you're coming from the Android angle:
String str = TextUtils.join(",", arr);
You can modify the above depending on what characters, if any, you want in between stri...
Replace a character at a specific index in a string?
...
and what makes your solution better?
– dpp
May 3 '12 at 1:43
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