大约有 40,000 项符合查询结果（耗时：0.0408秒） [XML]
MySQL select 10 random rows from 600K rows fast
How can I best write a query that selects 10 rows randomly from a total of 600k?
26 Answers
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Convert Rows to columns using 'Pivot' in SQL Server
...9, 3, 87);
If your values are known, then you will hard-code the query:
select *
from
(
select store, week, xCount
from yt
) src
pivot
(
sum(xcount)
for week in ([1], [2], [3])
) piv;
See SQL Demo
Then if you need to generate the week number dynamically, your code will be:
DECLARE @c...
Export database schema into SQL file
...ht click the database you want to generate scripts for (not the table) and select tasks - generate scripts
Next, select the requested table/tables, views, stored procedures, etc (from select specific database objects)
Click advanced - select the types of data to script
Click Next and finish
MSDN...
Remove outline from select box in FF
Is it possible to remove the dotted line surrounding a selected item in a select element?
12 Answers
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quick random row selection in Postgres
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You might want to experiment with OFFSET, as in
SELECT myid FROM mytable OFFSET floor(random()*N) LIMIT 1;
The N is the number of rows in mytable. You may need to first do a SELECT COUNT(*) to figure out the value of N.
Update (by Antony Hatchkins)
You must use floor he...
jQuery - getting custom attribute from selected option
...
You're adding the event handler to the <select> element.
Therefore, $(this) will be the dropdown itself, not the selected <option>.
You need to find the selected <option>, like this:
var option = $('option:selected', this).attr('mytag');
...
How to get multiple counts with one SQL query?
...tion. This is basically the same thing as a PIVOT function in some RDBMS:
SELECT distributor_id,
count(*) AS total,
sum(case when level = 'exec' then 1 else 0 end) AS ExecCount,
sum(case when level = 'personal' then 1 else 0 end) AS PersonalCount
FROM yourtable
GROUP BY distributor_id
...
Efficiently convert rows to columns in sql server
...ou can use the PIVOT function to transform the data from rows to columns:
select Firstname, Amount, PostalCode, LastName, AccountNumber
from
(
select value, columnname
from yourtable
) d
pivot
(
max(value)
for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber)
) piv;
S...
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
...
How to send data to local clipboard from a remote SSH session
...
I often to this in vim. To do so, select what you want to copy in visual mode, then type: :'<,'>w !ssh desktop pbcopy
– Mike Brennan
Nov 30 '12 at 5:04
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