大约有 40,000 项符合查询结果（耗时：0.0490秒） [XML]
What's the false operator in C# good for?
...er that nullity could be checked explicitly.
Comparing to SQL, imagine a table Table with 3 rows with value Foo set to true, 3 rows with value Foo set to false and 3 rows with value Foo set to null.
SELECT COUNT(*) FROM Table WHERE Foo = TRUE OR Foo = FALSE
6
In order to count all rows you'd ha...
Why should I capitalize my SQL keywords? [duplicate]
...nk the latter is more readable. You can easily separate the keywords from table and column names, etc.
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What is the difference between ExecuteScalar, ExecuteReader and ExecuteNonQuery?
...ny result set with multiple rows/columns (e.g., SELECT col1, col2 from sometable).
ExecuteNonQuery is typically used for SQL statements without results (e.g., UPDATE, INSERT, etc.).
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Is it a good idea to index datetime field in mysql?
.... In my application I will have many rows for example I currently have one table with 4 million records. Most of my queries use datetime clause to select data. Is it a good idea to index datetime fields in mysql database?
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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...
Elements order in a “for (… in …)” loop
Does the "for…in" loop in Javascript loop through the hashtables/elements in the order they are declared? Is there a browser which doesn't do it in order?
The object I wish to use will be declared once and will never be modified.
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Use a LIKE statement on SQL Server XML Datatype
If you have a varchar field you can easily do SELECT * FROM TABLE WHERE ColumnA LIKE '%Test%' to see if that column contains a certain string.
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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 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...
Convert HTML to PDF in .NET
...use of iTextSharp for this but it does not perform well when it encounters tables and the layout just gets messy.
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