大约有 45,000 项符合查询结果（耗时：0.0335秒） [XML]
How can I drop all the tables in a PostgreSQL database?
...
You can write a query to generate a SQL script like this:
select 'drop table "' || tablename || '" cascade;' from pg_tables;
Or:
select 'drop table if exists "' || tablename || '" cascade;' from pg_tables;
In case some tables are automatically dropped due to cascade option in a...
How to call Android contacts list?
...TION_PICK on the People.CONTENT_URI, then return to this Activity when the selection is made (or canceled).
startActivityForResult(intent, PICK_CONTACT);
3. Listening for the Result
Also in your Activity, override the onActivityResult method to listen for the return from the 'select a contact' A...
Convert varchar to uniqueidentifier in SQL Server
...
DECLARE @uuid VARCHAR(50)
SET @uuid = 'a89b1acd95016ae6b9c8aabb07da2010'
SELECT CAST(
SUBSTRING(@uuid, 1, 8) + '-' + SUBSTRING(@uuid, 9, 4) + '-' + SUBSTRING(@uuid, 13, 4) + '-' +
SUBSTRING(@uuid, 17, 4) + '-' + SUBSTRING(@uuid, 21, 12)
AS UNIQUEIDENTIFIER)
...
T-SQL stored procedure that accepts multiple Id values
...nguages only.
XML. Very good for inserting many rows; may be overkill for SELECTs.
Table of Numbers. Higher performance/complexity than simple iterative method.
Fixed-length Elements. Fixed length improves speed over the delimited string
Function of Numbers. Variations of Table of Numbers and fixed...
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...
Fetch frame count with ffmpeg
.... See Edit lists below.
ffprobe: Query the container
ffprobe -v error -select_streams v:0 -show_entries stream=nb_frames -of default=nokey=1:noprint_wrappers=1 input.mp4
This is a fast method.
Not all formats (such as Matroska) will report the number of frames resulting in the output of N/A. ...
Unable to run app in Simulator: Xcode beta 6 iOS 8
...r dialog shows up, you still would have access to the iOS Simulator's menu
Select Hardware > Device > Manage Devices
Click on the little + sign at the bottom
Add (if missing) all the devices that you want, or delete and recreate the ones malfunctioning.
If anyone of the simulator is not workin...
How to create id with AUTO_INCREMENT on Oracle?
...LACE TRIGGER dept_bir
BEFORE INSERT ON departments
FOR EACH ROW
BEGIN
SELECT dept_seq.NEXTVAL
INTO :new.id
FROM dual;
END;
/
UPDATE:
IDENTITY column is now available on Oracle 12c:
create table t1 (
c1 NUMBER GENERATED by default on null as IDENTITY,
c2 VARCHAR2(10)
);
...
Standard alternative to GCC's ##__VA_ARGS__ trick?
...ine REST_HELPER_TWOORMORE(first, ...) , __VA_ARGS__
#define NUM(...) \
SELECT_10TH(__VA_ARGS__, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE,\
TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, ONE, throwaway)
#define SELECT_10TH(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, ...) a10
int
main...
Selecting last element in JavaScript array [duplicate]
...gth less 1.
Mozilla Docs on Slice
Performance of the various methods for selecting last array element
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