大约有 44,000 项符合查询结果（耗时：0.0384秒） [XML]
When would anyone use a union? Is it a remnant from the C-only days?
...own Variant type:
struct my_variant_t {
int type;
union {
char char_value;
short short_value;
int int_value;
long long_value;
float float_value;
double double_value;
void* ptr_value;
};
};
Then you would use it such as:
/* const...
Escape double quotes in parameter
...ve all the quotes here and place the parameter value in a string used in a select query filter? Can someone help?
– SFDC_Learner
Nov 24 '15 at 16:21
...
What is the email subject length limit?
How many characters are allowed to be in the subject line of Internet email?
I had a scan of The RFC for email but could not see specifically how long it was allowed to be.
I have a colleague that wants to programmatically validate for it.
...
How do I find a “gap” in running counter with SQL?
...
In MySQL and PostgreSQL:
SELECT id + 1
FROM mytable mo
WHERE NOT EXISTS
(
SELECT NULL
FROM mytable mi
WHERE mi.id = mo.id + 1
)
ORDER BY
id
LIMIT 1
In SQL Server:
SELECT TOP 1
i...
How to get next/previous record in MySQL?
...
next:
select * from foo where id = (select min(id) from foo where id > 4)
previous:
select * from foo where id = (select max(id) from foo where id < 4)
...
How do I check if an integer is even or odd? [closed]
...tring();
if (String.IsNullOrEmpty(foo))
return Evenness.Unknown;
char bar = foo[foo.Length - 1];
switch (bar)
{
case '0':
case '2':
case '4':
case '6':
case '8':
return Evenness.Even;
case '1':
case '3':
case '5':
case '7':
case...
How to see if an object is an array without using reflection?
...d have to check if the object is an instanceof boolean[], byte[], short[], char[], int[], long[], float[], double[], or Object[], if you want to detect all array types.
Also, an int[][] is an instanceof Object[], so depending on how you want to handle nested arrays, it can get complicated.
For the t...
How to reset postgres' primary key sequence when it falls out of sync?
...
-- 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...
Why is C so fast, and why aren't other languages as fast or faster? [closed]
...what the machine does can be seen in the rules that govern the widening of char objects for use in expressions: whether the values of char objects widen to signed or unsigned quantities typically depends on which byte operation is more efficient on the target machine.
...
SQL JOIN and different types of JOINs
...
There are relatively new LATERAL JOIN .. SELECT * FROM r1, LATERAL fx(r1)
– Pavel Stehule
Jul 30 '13 at 11:52
13
...