大约有 48,000 项符合查询结果（耗时：0.0880秒） [XML]
Insert, on duplicate update in PostgreSQL?
...mple 38-2. Exceptions with UPDATE/INSERT
This example uses exception handling to perform either UPDATE or INSERT, as appropriate:
CREATE TABLE db (a INT PRIMARY KEY, b TEXT);
CREATE FUNCTION merge_db(key INT, data TEXT) RETURNS VOID AS
$$
BEGIN
LOOP
-- first try to update the key...
OPTION (RECOMPILE) is Always Faster; Why?
...istics. This can be done by running the following:
EXEC sp_updatestats
And then recreating your execution plan. This will ensure that when your execution plan is created it will be using the latest information.
Adding OPTION(RECOMPILE) rebuilds the execution plan every time that your query exe...
What are the main purposes of using std::forward and which problems it solves?
...arding, std::forward is used to convert the named rvalue references t1 and t2 to unnamed rvalue references. What is the purpose of doing that? How would that affect the called function inner if we leave t1 & t2 as lvalues?
...
Purge or recreate a Ruby on Rails database
...ave a dev Ruby on Rails database full of data. I want to delete everything and rebuild the database. I'm thinking of using something like:
...
How do I add comments to package.json for npm install?
I've got a simple package.json file and I want to add a comment. Is there a way to do this, or are there any hacks to make this work?
...
Javascript fuzzy search that makes sense
...arch JavaScript library to filter an array. I've tried using fuzzyset.js and fuse.js , but the results are terrible (there are demos you can try on the linked pages).
...
Difference between android-support-v7-appcompat and android-support-v4
I wanted to know the difference between android-support-v4.jar
and android-support-v7-appcompat.jar . If I want to add appcompat Action Bar in my application do I need to add both android-support-v7-appcompat.jar and android-support-v4.jar or only android-support-v7-appcompat.jar .
...
Can I use git diff on untracked files?
...diff output, or is my best bet to use git add on the newly created files and the existing files I have edited, then use:
...
Use ffmpeg to add text subtitles [closed]
...le is available, but not burned into the video? I can show if I want on demand?
– Sun
Jan 2 '16 at 6:36
3
...
Apply multiple functions to multiple groupby columns
...
The second half of the currently accepted answer is outdated and has two deprecations. First and most important, you can no longer pass a dictionary of dictionaries to the agg groupby method. Second, never use .ix.
If you desire to work with two separate columns at the same time I wou...