大约有 40,000 项符合查询结果（耗时：0.0495秒） [XML]
SQLite select where empty?
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It looks like you can simply do:
SELECT * FROM your_table WHERE some_column IS NULL OR some_column = '';
Test case:
CREATE TABLE your_table (id int, some_column varchar(10));
INSERT INTO your_table VALUES (1, NULL);
INSERT INTO your_table VALUES (2, '');
INSERT INTO your_t...
How to create ENUM type in SQLite?
I need to convert a table from MySQL to SQLite, but I can't figure out how to convert an enum field, because I can't find ENUM type in SQLite.
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Possibility of duplicate Mongo ObjectId's being generated in two different collections?
...of different "types" in the same collection, so why not just put your two "tables" in the same collection. They would share the same _id space, and thus, would be guaranteed unique. Switching from "prospective" to "registered" would be a simple flipping of a field...
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What is the fastest integer division supporting division by zero no matter what the result is?
...y accessible in C through using idiom. That is why it so hard to make a portable multiple precision integer library in C without resorting to (inline) assembly. My guess is that most decent compilers will understand the above idiom.
Another way of avoiding branches, as also remarked in some of the ...
Simple basic explanation of a Distributed Hash Table (DHT)
...tore a particular key is found by hashing that key, so in effect your hash-table buckets are now independent nodes in a network.
This gives a lot of fault-tolerance and reliability, and possibly some performance benefit, but it also throws up a lot of headaches. For example, what happens when a nod...
Select values from XML field in SQL Server 2008
...alue('(/person//lastName/node())[1]', 'nvarchar(max)') as LastName
FROM [myTable]
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Postgis installation: type “geometry” does not exist
I am trying to create table with Postgis. I do it by this page . But when I import postgis.sql file, I get a lot of errors:
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GCC -fPIC option
...DIT: In response to comment.
If your code is compiled with -fPIC, it's suitable for inclusion in a library - the library must be able to be relocated from its preferred location in memory to another address, there could be another already loaded library at the address your library prefers.
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Is it possible to force Excel recognize UTF-8 CSV files automatically?
...nsion XLS you will get the correct result.
Content of UTF8 XLS file:
<table>
<tr><td>Colum1</td><td>Column2</td></tr>
<tr><td>Val1</td><td>Val2</td></tr>
<tr><td>Авиабилет</td><td>Tλλη...
Hex transparency in colors [duplicate]
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Here's a correct table of percentages to hex values. E.g. for 50% white you'd use #80FFFFFF.
100% — FF
95% — F2
90% — E6
85% — D9
80% — CC
75% — BF
70% — B3
65% — A6
60% — 99
55% — 8C
50% — 80
45% — 73
40% — 66
35%...