大约有 47,000 项符合查询结果（耗时：0.0260秒） [XML]
PadLeft function in T-SQL
...
I believe this may be what your looking for:
SELECT padded_id = REPLACE(STR(id, 4), SPACE(1), '0')
FROM tableA
or
SELECT REPLACE(STR(id, 4), SPACE(1), '0') AS [padded_id]
FROM tableA
I haven't tested the syntax on the 2nd example. I'm not sure if that works 100%...
Select row with most recent date per user
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Query:
SQLFIDDLEExample
SELECT t1.*
FROM lms_attendance t1
WHERE t1.time = (SELECT MAX(t2.time)
FROM lms_attendance t2
WHERE t2.user = t1.user)
Result:
| ID | USER | TIME | IO |
---------------------------...
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 ...
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Tri-state Check box in HTML?
...lternative would be to play with the checkbox transparency
for the "some selected" state (as Gmail does used to
do in previous versions). It will require some javascript and a CSS
class. Here I put a particular example that handles a list with
checkable items and a checkbox that allows to se...
HTML select form with option to enter custom value
...users can enter custom text value or choose from drop down. A regular <select> only offers drop down options.
6 Ans...
Multiple select statements in Single query
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SELECT (
SELECT COUNT(*)
FROM user_table
) AS tot_user,
(
SELECT COUNT(*)
FROM cat_table
) AS tot_cat,
(
SELECT COUNT(*)
FROM course_table
) AS tot_course
...
How to do a FULL OUTER JOIN in MySQL?
...MPLE transcribed from this SO question you have:
with two tables t1, t2:
SELECT * FROM t1
LEFT JOIN t2 ON t1.id = t2.id
UNION
SELECT * FROM t1
RIGHT JOIN t2 ON t1.id = t2.id
The query above works for special cases where a FULL OUTER JOIN operation would not produce any duplicate rows. The quer...
Unioning two tables with different number of columns
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Add extra columns as null for the table having less columns like
Select Col1, Col2, Col3, Col4, Col5 from Table1
Union
Select Col1, Col2, Col3, Null as Col4, Null as Col5 from Table2
share
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Return Boolean Value on SQL Select Statement
How to return a boolean value on SQL Select Statement?
9 Answers
9
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MySQL: determine which database is selected?
After calling mysql_select_db to grab a database, is there any way to later output the name of the database that is currently selected? This seems very basic but I couldn't find anything on php.net or stackoverflow (all results are for "no database selected").
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