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Switch statement: must default be the last case?
...ice:
Any statement may be preceded by a
prefix that declares an identifier as
a label name. Labels in themselves do
not alter the flow of control, which
continues unimpeded across them.
Edit: The code within a switch is nothing special; it is a normal block of code as in an if-stateme...
Difference between VARCHAR and TEXT in MySQL [duplicate]
...e stored string.
cannot be (fully) part of an index. One would need to specify a prefix length.
VARCHAR(M)
variable max size of M characters
M needs to be between 1 and 65535
takes 1 + c bytes (for M ≤ 255) or 2 + c (for 256 ≤ M ≤ 65535) bytes of disk space where c is the length of the sto...
Convert light frequency to RGB?
...(double Wavelength) {
double factor;
double Red, Green, Blue;
if((Wavelength >= 380) && (Wavelength < 440)) {
Red = -(Wavelength - 440) / (440 - 380);
Green = 0.0;
Blue = 1.0;
} else if((Wavelength >= 440) && (Wavelength < 490)) {
...
What issues should be considered when overriding equals and hashCode in Java?
...reflexive, symmetric, and transitive). In addition, it must be consistent (if the objects are not modified, then it must keep returning the same value). Furthermore, o.equals(null) must always return false.
hashCode() (javadoc) must also be consistent (if the object is not modified in terms of equa...
Check if a string is null or empty in XSLT
How can I check if a value is null or empty with XSL ?
14 Answers
14
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'IF' in 'SELECT' statement - choose output value based on column values
I need amount to be amount if report.type='P' and -amount if report.type='N' . How do I add this to the above query?
...
SQL: How to properly check if a record exists
...rs in recent RDBMS's optimize SELECT COUNT(*) anyway, so while there is a difference in theory (and older databases), you shouldn't notice any difference in practice.
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MySQL: Insert record if not exists in table
...Rupert | Somewhere | 022 |
+----+--------+-----------+------+
Insert a different record:
INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'John', 'Doe', '022') AS tmp
WHERE NOT EXISTS (
SELECT name FROM table_listnames WHERE name = 'John'
) LIMIT 1;
Query OK, 1 row af...
How to check if a symlink exists
I'm trying to check if a symlink exists in bash. Here's what I've tried.
8 Answers
8
...
Int division: Why is the result of 1/3 == 0?
...do any rounding, but you can think of it that way still.)
Also, note that if both operands (numbers) are given as floats; 3.0 and 1.0, or even just the first, then floating-point arithmetic is used, giving you 0.333....
sha...