大约有 6,100 项符合查询结果（耗时：0.0293秒） [XML]
Is there a typical state machine implementation pattern?
...
I prefer to use a table driven approach for most state machines:
typedef enum { STATE_INITIAL, STATE_FOO, STATE_BAR, NUM_STATES } state_t;
typedef struct instance_data instance_data_t;
typedef state_t state_func_t( instance_data_t *data );
s...
Does MySQL ignore null values on unique constraints?
... MySQL allows multiple NULLs in a column with a unique constraint.
CREATE TABLE table1 (x INT NULL UNIQUE);
INSERT table1 VALUES (1);
INSERT table1 VALUES (1); -- Duplicate entry '1' for key 'x'
INSERT table1 VALUES (NULL);
INSERT table1 VALUES (NULL);
SELECT * FROM table1;
Result:
x
NULL
NULL...
SQL Server: SELECT only the rows with MAX(DATE)
I have a table of data (the db is MSSQL):
11 Answers
11
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Simulating group_concat MySQL function in Microsoft SQL Server 2005?
...to do this. Lots of ideas out there, though.
Best one I've found:
SELECT table_name, LEFT(column_names , LEN(column_names )-1) AS column_names
FROM information_schema.columns AS extern
CROSS APPLY
(
SELECT column_name + ','
FROM information_schema.columns AS intern
WHERE extern.table_n...
SQL Server query - Selecting COUNT(*) with DISTINCT
In SQL Server 2005 I have a table cm_production that lists all the code that's been put into production. The table has a ticket_number, program_type, and program_name and push_number along with some other columns.
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Vertically align text next to an image?
...lt;/div>
Multiple-lines vertical-align:middle
<div style="display:table;width:30px;height:60px;">
<div style="display:table-cell;height:30px;">This is positioned in the middle</div>
</div>
If you must support ancient versions of IE <= 7
In order to get this to w...
MySQL vs MongoDB 1000 reads
...e been very excited about MongoDb and have been testing it lately. I had a table called posts in MySQL with about 20 million records indexed only on a field called 'id'.
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SQLite - How do you join tables from different databases?
...econd SQLite database, but I'm having a hard time figuring out how to join tables from the different databases.
3 Answers
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How to quickly edit values in table in SQL Server Management Studio?
...> "Edit Top 200 Rows" from Object Explorer, is there a quick way to open a table in Edit mode where I can just quickly modify the value of a cell?
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What is the best way to remove a table row with jQuery?
What is the best method for removing a table row with jQuery?
17 Answers
17
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