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How to correctly implement custom iterators and const_iterators?
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They often forget that iterator must convert to const_iterator but not the other way around. Here is a way to do that:
template<class T, class Tag = void>
class IntrusiveSlistIterator
: public std::iterator<std::forward_iterator_tag, T>
{
typ...
How to write a foreach in SQL Server?
...) IN (''VARCHAR'', ''CHAR'', ''NCHAR'', ''NVARCHAR'') THEN ''('' + REPLACE(CONVERT(VARCHAR(10), max_length), ''-1'', ''MAX'') + '')''
WHEN type_name(system_type_id) IN (''DECIMAL'', ''NUMERIC'') THEN ''('' + CONVERT(VARCHAR(10), precision) + '', '' + CONVERT(VARCHAR(10), scale) + '')''
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How can I convert a string to a number in Perl?
I have a string which holds a decimal value in it and I need to convert that string into a floating point variable. So an example of the string I have is "5.45" and I want a floating point equivalent so I can add .1 to it. I have searched around the internet, but I only see how to convert a string t...
What is the difference between related SQLite data-types like INT, INTEGER, SMALLINT and TINYINT?
...RDBMSes. Everything, internally, is stored as text. Data types are coerced/converted into various storage locations based on affinities (ala data types assigned to columns).
The best thing that I'd recommend you do is to :
Temporarily forget everything you used to know about standalone database d...
How to calculate percentage with a SQL statement
...ase you overflow on the 100 multiplication (e.g. Arithmetic overflow error converting expression to data type int), replace it with division in denominator instead: cast((count(*) / (sum(count(*)) over() / 100)) AS DECIMAL(18, 2)) as Percentage
– Nikita G.
Jan ...
Pandas DataFrame column to list [duplicate]
...ta in pandas dataframe has both int64 and float64. When I do df.values, it converts the int64 to float64 and the whole array has dtype of float64. Any clues how to deal with this ?
– ShikharDua
Apr 21 '16 at 21:00
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Unable to cast object of type 'System.DBNull' to type 'System.String`
... the first case @Alexander mentions -not matching any row- you can rely on Convert.ToString or any other Convert method if you are fine with the value they return when converting from null: empty string for strings, 0 for numeric values, false for boolean, MinValue for DateTime... msdn.microsoft.com...
Convert Rows to columns using 'Pivot' in SQL Server
...o.
The dynamic version, generates the list of week numbers that should be converted to columns. Both give the same result:
| STORE | 1 | 2 | 3 |
---------------------------
| 101 | 138 | 282 | 220 |
| 102 | 96 | 212 | 123 |
| 105 | 37 | 78 | 60 |
| 109 | 59 | 97 | 87 |
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Converting string to title case
...ry/…): "However, this method does not currently provide proper casing to convert a word that is entirely uppercase, such as an acronym" - you should probably just ToLower() it first (I know this is old, but just in case someone else stumbles on it and wonders why!)
– nizmow
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What is the equivalent of bigint in C#?
...r how much they look alike. Part of the reason is that SQL will frequently convert Int/BigInt to Numeric as part of the normal processing. So when it goes to OLE or .NET the required conversion is NUMERIC to INT.
We don't often notice since the printed value looks the same.
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