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What is the difference between Non-Repeatable Read and Phantom Read?
...e query have the same value before and after, but different rows are being selected (because B has deleted or inserted some). Example: select sum(x) from table; will return a different result even if none of the affected rows themselves have been updated, if rows have been added or deleted.
In ...
What is a good reason to use SQL views?
...one extra column active.
If your system(s) have gazillion queries that do SELECT whatever FROM T_OLD WHERE whatever, you have two choices for the roll-out:
1) Cold Turkey - Change the DB, and at the same time, change, test and release numerous pieces of code which contained said query. VERY hard t...
MySQL/SQL: Group by date only on a Datetime column
...
Cast the datetime to a date, then GROUP BY using this syntax:
SELECT SUM(foo), DATE(mydate) FROM a_table GROUP BY DATE(a_table.mydate);
Or you can GROUP BY the alias as @orlandu63 suggested:
SELECT SUM(foo), DATE(mydate) DateOnly FROM a_table GROUP BY DateOnly;
Though I don't think...
COUNT DISTINCT with CONDITIONS
...
You can try this:
select
count(distinct tag) as tag_count,
count(distinct (case when entryId > 0 then tag end)) as positive_tag_count
from
your_table_name;
The first count(distinct...) is easy.
The second one, looks somewhat complex...
Sqlite: CURRENT_TIMESTAMP is in GMT, not the timezone of the machine
...a unix
timestamp 1092941466, and compensate
for your local timezone.
SELECT datetime(1092941466, 'unixepoch', 'localtime');
That didn't look like it fit my needs, so I tried changing the "datetime" function around a bit, and wound up with this:
select datetime(timestamp, 'localtime')
That...
Get screen width and height in Android
...e answer by parag and SpK to align with current SDK backward compatibility from deprecated methods:
int Measuredwidth = 0;
int Measuredheight = 0;
Point size = new Point();
WindowManager w = getWindowManager();
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
w.getDefault...
How to remove files that are listed in the .gitignore but still on the repository?
...nored, i added them to the .gitignore but, of course, they are not removed from my repository.
6 Answers
...
Get Selected index of UITableView
I want to have selected index for UITableView .
I have written following code:
5 Answers
...
Change name of iPhone app in Xcode 4
...veryone:
1.In the project contents pane at left, click the Folder icon.
2.Select the top-level blue line representing the project.
3.If you don't have the Inspector pane (right pane) open, click the button to enable it. This is the third button in the "View" toolbar towards the upper right corner...
ReactJS Two components communicating
...te is also increasing in complexity, as we need to
manage active routes, selected tabs, spinners, pagination controls,
and so on.
Managing this ever-changing state is hard. If a model can update
another model, then a view can update a model, which updates another
model, and this, in tur...