大约有 40,000 项符合查询结果（耗时：0.0186秒） [XML]
Select rows which are not present in other table
...task, all of them standard SQL.
NOT EXISTS
Often fastest in Postgres.
SELECT ip
FROM login_log l
WHERE NOT EXISTS (
SELECT -- SELECT list mostly irrelevant; can just be empty in Postgres
FROM ip_location
WHERE ip = l.ip
);
Also consider:
What is easier to read in EXISTS...
How to select/get drop down option in Selenium 2
...converting my selenium 1 code to selenium 2 and can't find any easy way to select a label in a drop down menu or get the selected value of a drop down. Do you know how to do that in Selenium 2?
...
Unioning two tables with different number of columns
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Add extra columns as null for the table having less columns like
Select Col1, Col2, Col3, Col4, Col5 from Table1
Union
Select Col1, Col2, Col3, Null as Col4, Null as Col5 from Table2
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How can I confirm a database is Oracle & what version it is using SQL?
I'm building an installer for an application. The user gets to select a datasource they have configured and nominate what type of database it is. I want to confirm that the database type is indeed Oracle, and if possible, what version of Oracle they are running by sending a SQL statement to the dat...
Rails 3: Get Random Record
...You can use the following trick on an indexed column (PostgreSQL syntax):
select *
from my_table
where id >= trunc(
random() * (select max(id) from my_table) + 1
)
order by id
limit 1;
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Add a number to each selection in Sublime Text 2, incremented once per selection
...
M represents the step size which will be added to the index for
each selection.
P must be > 0 and will be used to pad the index with
leading zeroes.
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Oracle SELECT TOP 10 records
I have an big problem with an SQL Statement in Oracle. I want to select the TOP 10 Records ordered by STORAGE_DB which aren't in a list from an other select statement.
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How do I query if a database schema exists
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Are you looking for sys.schemas?
IF NOT EXISTS (SELECT * FROM sys.schemas WHERE name = 'jim')
BEGIN
EXEC('CREATE SCHEMA jim')
END
Note that the CREATE SCHEMA must be run in its own batch (per the answer below)
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MySQL Great Circle Distance (Haversine formula)
...ults. To search by kilometers instead of miles, replace 3959 with 6371.
SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) )
* cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin(radians(lat)) ) ) AS distance
FROM markers
HAVING distance < 25
ORDER BY distance ...