大约有 40,000 项符合查询结果（耗时：0.0155秒） [XML]
What is the most ridiculous pessimization you've seen? [closed]
...nearly all their tables have an associated archive table, and most queries select from views that UNION the pairs of tables. Performance is as you would expect!
– Tony Andrews
Mar 26 '09 at 13:32
...
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
...Shouldn't the threads in the connection pool be kept active by firing the "select 1" validation query? Why would they get closed by prolonged inactivity when we have set the evictor to run at shorter time intervals than the mysql server timeout?
– Farhad
Sep 2 ...
ERROR 2006 (HY000): MySQL server has gone away
...L/MariaDB server.
Double check the value was set properly by:
mysql -sve "SELECT @@max_allowed_packet" # or:
mysql -sve "SHOW VARIABLES LIKE 'max_allowed_packet'"
You got a timeout from the TCP/IP connection on the client side.
Solution: Increase wait_timeout variable.
You tried to run a query a...
Get the week start date and week end date from week number
...y other weird value to test it */
DECLARE @d DATETIME
SET @d = GETDATE()
SELECT
@d ThatDate,
DATEADD(dd, 0 - (@@DATEFIRST + 5 + DATEPART(dw, @d)) % 7, @d) Monday,
DATEADD(dd, 6 - (@@DATEFIRST + 5 + DATEPART(dw, @d)) % 7, @d) Sunday
...
error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)' — Miss
...ate to where your mysql.sock file is located
Right click on the file and select Make Link
Rename the Link File to mysqld.sock then Right click on the file and Cut it
Go to /var/run and create a folder called mysqld and enter it
Now right click and Paste the Link File
Voila! You will now have a mys...
Sql Server string to date conversion
...what you're looking for. It wont be hard to adapt:
Declare @d datetime
select @d = getdate()
select @d as OriginalDate,
convert(varchar,@d,100) as ConvertedDate,
100 as FormatValue,
'mon dd yyyy hh:miAM (or PM)' as OutputFormat
union all
select @d,convert(varchar,@d,101),101,'mm/dd/yy'
union al...
Force drop mysql bypassing foreign key constraint
...
If you are using phpmyadmin then this feature is already there.
Select the tables you want to drop
From the dropdown at the bottom of tables list, select drop
A new page will be opened having checkbox at the bottom saying
"Foreign key check", uncheck it.
Confirm the deletion by accepting ...
How can I select from list of values in SQL Server
... would be to use a find an replace with UNION to get the distinct values.
SELECT 1
UNION SELECT 1
UNION SELECT 1
UNION SELECT 2
UNION SELECT 5
UNION SELECT 1
UNION SELECT 6
Applied to your long line of comma delimited text
Find and replace every comma with UNION SELECT
Add a SELECT in front of ...
Awk学习笔记 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...nd expression are optional
}
15. How-to
如何把一行竖排的数据转换成横排？
awk '{printf("%s,",$1)}' filename
awk 笔记
How to get a list of MySQL views?
...to leave the "IN database_name" away if you look for view in the currently selected DB.
– kraftb
Jun 2 '15 at 17:11
To...