大约有 40,000 项符合查询结果（耗时：0.0428秒） [XML]
Passing an array to a query using a WHERE clause
...FROM galleries WHERE id IN (1); SELECT password FROM users;/*). Change the table & column names to something you have in your database and try that query, check out the results. You'll find a list of passwords as your result, rather than a list of galleries. Depending on how the data is output, ...
Most efficient T-SQL way to pad a varchar on the left to a certain length?
...on cleaner, it is not very efficient in terms of execution time. The Tally table I used has 64,000 records. Kudos to Martin Smith for pointing out execution time efficiency.
SET STATISTICS TIME ON
select FORMAT(N, 'd10') as padWithZeros from Tally
SET STATISTICS TIME OFF
SQL Server Execution Tim...
Scheduling R Script
..., to run scheduler first install below packages
install.packages('data.table')
install.packages('knitr')
install.packages('miniUI')
install.packages('shiny')
install.packages("taskscheduleR", repos = "http://www.datatailor.be/rcube", type =
"source")
After installing go to
**TOOLS...
How to load an ImageView by URL in Android? [closed]
...
memory twice. Bitmap memory is managed
by using a weak reference hash table,
so as soon as the image is no longer
used by you, it will be garbage
collected automatically.
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How do I conditionally apply CSS styles in AngularJS?
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I have found problems when applying classes inside table elements when I had one class already applied to the whole table (for example, a color applied to the odd rows <myClass tbody tr:nth-child(even) td>). It seems that when you inspect the element with Developer Tool...
How to check if there exists a process with a given pid in Python?
...ef pid_exists(pid):
"""Check whether pid exists in the current process table.
UNIX only.
"""
if pid < 0:
return False
if pid == 0:
# According to "man 2 kill" PID 0 refers to every process
# in the process group of the calling process.
# On cert...
Explicitly set Id with Doctrine when using “AUTO” strategy
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In case the entity is part of a class table inheritance you need to change the id-generator in the class metadata for both entities (the entity you are persisting and the root entity)
sha...
Convert Unix timestamp into human readable date using MySQL
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Use FROM_UNIXTIME():
SELECT
FROM_UNIXTIME(timestamp)
FROM
your_table;
See also: MySQL documentation on FROM_UNIXTIME().
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How do I check if a SQL Server text column is empty?
I am using SQL Server 2005. I have a table with a text column and I have many rows in the table where the value of this column is not null, but it is empty. Trying to compare against '' yields this response:
...
PostgreSQL: How to make “case-insensitive” query
...indexes to no longer be seekable. If this is a large or frequently queried table, that could cause trouble. Case-insensitive collation, citext, or a function-based index will improve performance.
– Jordan
Aug 10 '11 at 4:23
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