大约有 40,000 项符合查询结果（耗时：0.0402秒） [XML]
Simplest way to do a recursive self-join?
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WITH q AS
(
SELECT *
FROM mytable
WHERE ParentID IS NULL -- this condition defines the ultimate ancestors in your chain, change it as appropriate
UNION ALL
SELECT m.*
FROM mytable m
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Can you have if-then-else logic in SQL? [duplicate]
I need to do select data from a table based on some kind of priority like so:
7 Answers
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How to check if a string contains only digits in Java [duplicate]
...ves you the actual result: \d
References:
Java Regular Expressions
Java Character Escape Sequences
Edit: due to some confusion in other answers, I am writing a test case and will explain some more things in detail.
Firstly, if you are in doubt about the correctness of this solution (or other...
COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
...for all your queries that need to count everything, even for joins, use *
SELECT boss.boss_id, COUNT(subordinate.*)
FROM boss
LEFT JOIN subordinate on subordinate.boss_id = boss.boss_id
GROUP BY boss.id
But don't use COUNT(*) for LEFT joins, as that will return 1 even if the subordinate table doe...
Android Spinner: Get the selected item change event
How can you set the event listener for a Spinner when the selected item changes?
16 Answers
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How do I use ROW_NUMBER()?
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For the first question, why not just use?
SELECT COUNT(*) FROM myTable
to get the count.
And for the second question, the primary key of the row is what should be used to identify a particular row. Don't try and use the row number for that.
If you returned Ro...
Replace Line Breaks in a String C#
...to replace that particular environments implementation of new line control characters.
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How to set selected value on select using selectpicker plugin from bootstrap
I'm using the Bootstrap-Select plugin like this:
18 Answers
18
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How to split a delimited string into an array in awk?
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@WhiteWind: another way to "ensure" that | is seen as a char and not a special symbol is to put it between [] : ie, split($0, a, "[|]") # I like this better than '\|', in some cases, especially as some variant of regexp (perl vs grep vs .. others?) can have "|" interepreted l...
SQL Server: SELECT only the rows with MAX(DATE)
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If rownumber() over(...) is available for you ....
select OrderNO,
PartCode,
Quantity
from (select OrderNO,
PartCode,
Quantity,
row_number() over(partition by OrderNO order by DateEntered desc) as rn
from YourTable) a...