大约有 40,000 项符合查询结果（耗时：0.0162秒） [XML]
How to request a random row in SQL?
...
See this post: SQL to Select a random row from a database table. It goes through methods for doing this in MySQL, PostgreSQL, Microsoft SQL Server, IBM DB2 and Oracle (the following is copied from that link):
Select a random row with MySQL:
SELE...
With MySQL, how can I generate a column containing the record index in a table?
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You may want to try the following:
SELECT l.position,
l.username,
l.score,
@curRow := @curRow + 1 AS row_number
FROM league_girl l
JOIN (SELECT @curRow := 0) r;
The JOIN (SELECT @curRow := 0) part allows the variable initiali...
Get selected option from select element
I am trying to get the selected option from a dropdown and populate another item with that text, as follows. IE is barking up a storm and it doesn't work in Firefox:
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Using $_POST to get select option value from HTML
I use select as below:
8 Answers
8
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How to use NULL or empty string in SQL
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Select *
From Table
Where (col is null or col = '')
Or
Select *
From Table
Where IsNull(col, '') = ''
share
|
improve t...
How to reset postgres' primary key sequence when it falls out of sync?
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-- Login to psql and run the following
-- What is the result?
SELECT MAX(id) FROM your_table;
-- Then run...
-- This should be higher than the last result.
SELECT nextval('your_table_id_seq');
-- If it's not higher... run this set the sequence last to your highest id.
-- (wise to run...
Equivalent of LIMIT and OFFSET for SQL Server?
...nation it's better to write a query like this:
;WITH Results_CTE AS
(
SELECT
Col1, Col2, ...,
ROW_NUMBER() OVER (ORDER BY SortCol1, SortCol2, ...) AS RowNum
FROM Table
WHERE <whatever>
)
SELECT *
FROM Results_CTE
WHERE RowNum >= @Offset
AND RowNum < @Offset +...
Is it possible to specify condition in Count()?
...an use the fact that the count aggregate only counts the non-null values:
select count(case Position when 'Manager' then 1 else null end)
from ...
You can also use the sum aggregate in a similar way:
select sum(case Position when 'Manager' then 1 else 0 end)
from ...
...
Saving enum from select in Rails 4.1
...num.
I changed the input to be the following:
f.input :color, :as => :select, :collection => Wine.colors.keys.to_a
Which generated the following HTML:
<select id="wine_color" name="wine[color]">
<option value=""></option>
<option value="red">red</option>
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How do I select an entire row which has the largest ID in the table?
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You could use a subselect:
SELECT row
FROM table
WHERE id=(
SELECT max(id) FROM table
)
Note that if the value of max(id) is not unique, multiple rows are returned.
If you only want one such row, use @MichaelMior's answer,
SELEC...