大约有 48,000 项符合查询结果（耗时：0.0349秒） [XML]
Check if a Postgres JSON array contains a string
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As of PostgreSQL 9.4, you can use the ? operator:
select info->>'name' from rabbits where (info->'food')::jsonb ? 'carrots';
You can even index the ? query on the "food" key if you switch to the jsonb type instead:
alter table rabbits alter info type jsonb using ...
Count(*) vs Count(1) - SQL Server
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The optimizer recognizes it for what it is: trivial.
The same as EXISTS (SELECT * ... or EXISTS (SELECT 1 ...
Example:
SELECT COUNT(1) FROM dbo.tab800krows
SELECT COUNT(1),FKID FROM dbo.tab800krows GROUP BY FKID
SELECT COUNT(*) FROM dbo.tab800krows
SELECT COUNT(*),FKID FROM dbo.tab800krows GROU...
The current branch is not configured for pull No value for key branch.master.merge found in configur
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To fix this problem in Eclipse, open the Windows menu and select Show View / Other / Git Repositories.
From the Git Repositories tab:
expand your local repository
right click on Remote
click on Create Remote...
Remote name = origin
next to IRI press the Change button
CTRL+SPACE o...
How to return result of a SELECT inside a function in PostgreSQL?
... bigint
, ratio bigint) AS
$func$
BEGIN
RETURN QUERY
SELECT t.txt
, count(*) AS cnt -- column alias only visible inside
, (count(*) * 100) / _max_tokens -- I added brackets
FROM (
SELECT t.txt
FROM token t
WHERE t.charty...
How do I set up IntelliJ IDEA for Android applications?
...Program Files\Java\jdk{version}
Choose a New platform ( if there's not one selected ) , the SDK platform is the android platform at C:\Program Files\Android\android-sdk-windows.
Choose the android version.
Now you can write your program.
Compiling:
Near the Run button you need to select the drop...
Auto select file in Solution Explorer from its open tab
...times, I find myself right-clicking on a tab title and searching for Show/Select/Scroll-to this file in Solution Explorer , and I can't find it.
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Rank function in MySQL
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One option is to use a ranking variable, such as the following:
SELECT first_name,
age,
gender,
@curRank := @curRank + 1 AS rank
FROM person p, (SELECT @curRank := 0) r
ORDER BY age;
The (SELECT @curRank := 0) part allows the variable initializatio...
Select 50 items from list at random to write to file
... leaving the original population unchanged. The resulting list is
in selection order so that all sub-slices will also be valid random
samples. This allows raffle winners (the sample) to be partitioned
into grand prize and second place winners (the subslices).
Members of the popul...
PostgreSQL create table if not exists
..._mytable()
RETURNS void
LANGUAGE plpgsql AS
$func$
BEGIN
IF EXISTS (SELECT FROM pg_catalog.pg_tables
WHERE schemaname = 'myschema'
AND tablename = 'mytable') THEN
RAISE NOTICE 'Table myschema.mytable already exists.';
ELSE
CREATE TABLE myschema...
Select last N rows from MySQL
I want to select last 50 rows from MySQL database within column named id which is primary key . Goal is that the rows should be sorted by id in ASC order, that’s why this query isn’t working
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