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Is there any difference between GROUP BY and DISTINCT
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At least in Oracle 12 there do appear to be cases where DISTINCT, getting distinct values by UNION, and GROUP BY work differently. I just had a case earlier today where DISTINCT and distinct by UNION cause an oracle error, but G...
Does ARC support dispatch queues?
...ve-C runtime, the
* Objective-C GC compiler option to be disabled, and at least a Mac OS X 10.8
* or iOS 6.0 deployment target.
This means you can store your queue in an NSArray or NSDictionary, or in a property with one of the strong, weak, unsafe_unretained, assign, or retain attributes. It a...
How to design a product table for many kinds of product where each product has many parameters
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You have at least these five options for modeling the type hierarchy you describe:
Single Table Inheritance: one table for all Product types, with enough columns to store all attributes of all types. This means a lot of columns, most ...
How to determine if a number is odd in JavaScript
...ey Every number is comprised of a series of bits. All odd numbers have the least-significant (rightmost) bit set to 1, all even numbers 0. The x & 1 checks if the last bit is set in the number (because 1 Is a number with all bits set to 1 except for the least significant bit): If it is, the numb...
Regular expression for letters, numbers and - _
...omplicated.
The above regex also matches the empty string. If you need at least one character, then use + (one-or-more) instead of * (zero-or-more) for repetition.
In any case, you can further clarify your specification (always helps when asking regex question), but hopefully you can also learn ho...
Can I set enum start value in Java?
... lazy of the Java standards not to allow a value to be set for an enum. At least c# allows this AND is type-safe.
– csmith
Mar 20 '16 at 15:30
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How to concatenate columns in a Postgres SELECT?
...ring concatenation operator (||) accepts non-string
input, so long as at least one input is of a string type, as shown in
Table 9.8. For other cases, insert an explicit coercion to text [...]
Bold emphasis mine. The 2nd example (select a||', '||b from foo) works for any data types since the u...
What are the key differences between Apache Thrift, Google Protocol Buffers, MessagePack, ASN.1 and
...ures, the Encoding Rules define the on the wire encoding, and last but not least the Compiler transfers it to your programming language.
The free Compilers support C,C++,C#,Java, and Erlang to my knowledge. The (much to expensive and patent/licenses ridden) commercial compilers are very versatile, ...
John Carmack's Unusual Fast Inverse Square Root (Quake III)
...e task has now came down to calculate a0 and a1 in order for y to have the least difference from the exact value. They have calculated that the most appropriate values are:
a0 = 0x5f375a86
a1 = -0.5
So when you put this into equation you get:
y = 0x5f375a86 - 0.5*x
Which is the same as the lin...
Showing empty view when ListView is empty
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After at least an hour of trying various things, and having nothing work (showing the "empty" text in addition to data in the listview), this worked for me when using a ListView in an Activity instead of extending ListActivity. Thank...