大约有 40,000 项符合查询结果（耗时：0.0391秒） [XML]
Check for column name in a SqlDataReader object
...elp anyone setting their debugger to break on exceptions thrown.
GetSchemaTable() is also another suggestion in many answers. This would not be a preffered way of checking for a field's existance as it is not implemented in all versions (it's abstract and throws NotSupportedException in some versio...
How do I make a column unique and index it in a Ruby on Rails migration?
... What is the best way to do it? Also is there a way to index a column in a table?
8 Answers
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How are echo and print different in PHP? [duplicate]
...
$b ? print "true" : print "false";
print is also part of the precedence table which it needs to be if it
is to be used within a complex expression. It is just about at the bottom
of the precedence list though. Only , AND OR XOR are lower.
Parameter(s). The grammar is: echo expression [, expr...
Check if a Postgres JSON array contains a string
I have a table to store information about my rabbits. It looks like this:
4 Answers
4
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MySQL order by before group by
...hor is to use a subquery to return the max date and then join that to your table on both the post_author and the max date.
The solution should be:
SELECT p1.*
FROM wp_posts p1
INNER JOIN
(
SELECT max(post_date) MaxPostDate, post_author
FROM wp_posts
WHERE post_status='publish'
...
T-SQL: Selecting rows to delete via joins
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DELETE TableA
FROM TableA a
INNER JOIN TableB b
ON b.Bid = a.Bid
AND [my filter condition]
should work
share
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Max parallel http connections in a browser?
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A similar table can be found at http://sgdev-blog.blogspot.com/2014/01/maximum-concurrent-connection-to-same.html
– Jo.
Aug 26 '15 at 17:21
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Setting the MySQL root user password on OS X
... server in safe mode with privilege bypass
sudo mysqld_safe --skip-grant-tables;
In a new window connect to the database, set a new password and flush the permissions & quit:
mysql -u root
For MySQL older than MySQL 5.7 use:
UPDATE mysql.user SET Password=PASSWORD('your-password') WHERE ...
How do I obtain a Query Execution Plan in SQL Server?
...mat.
Notes:
Because there are so many factors involved (ranging from the table and index schema down to the data stored and the table statistics) you should always try to obtain an execution plan from the database you are interested in (normally the one that is experiencing a performance problem)....
Delete sql rows where IDs do not have a match from another table
I'm trying to delete orphan entries in a mysql table.
3 Answers
3
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