How to calculate superscript values in SQL - sql

Question

I have prices coming in my source file like below -
78-22¼,
78-18⅝
I need to calculate these price. For example for first case result should be 78-22.25. I searched a lot but found that SQL supports few of these characters only. Is there anyway to make sure we are able to calculate for whatever value we are getting. Solution in either SQL or PowerShell could work.

Answer 1

You could write a PowerShell function to convert the fractions to decimals:
PS ~> ConvertTo-Decimal '18⅝'
18.625
To do so, we'll need to write a function that:
Uses regex to identify and extract the integer and fraction parts
Uses [char]::GetNumericValue() to get the decimal representation of the fraction
Outputs the sum of the two
function ConvertTo-Decimal {
param(
[Parameter(Mandatory)]
[string]$InputObject
)
if($InputObject -match '^(-?)(\d+)(\p{No})?$'){
$baseValue = +$Matches[2]
if($Matches[3]){
$baseValue += [char]::GetNumericValue($Matches[3])
}
if($Matches[1] -eq '-'){
$baseValue *= -1
}
return $baseValue
}
return 0
}

Answer 2

Hoo this one was fun.
If you want to do it purley in TSQL give this a tug:
DECLARE #table TABLE (Glyph NVARCHAR(2), Dec DECIMAL(8,6))
INSERT INTO #table (Glyph, Dec) VALUES
(N'¼', 1.0/4),(N'½', 1.0/2),(N'¾', 3.0/4),(N'⅐', 1.0/7),
(N'⅑', 1.0/8),(N'⅒',1.0/10),(N'⅓', 1.0/3),(N'⅔', 2.0/3),
(N'⅕', 1.0/5),(N'⅖', 2.0/5),(N'⅗', 3.0/5),(N'⅘', 4.0/5),
(N'⅙', 1.0/6),(N'⅚', 5.0/6),(N'⅛', 1.0/8),(N'⅜', 3.0/8),
(N'⅝', 5.0/8),(N'⅞', 7.0/8),(N'⅟', 1.0/1)
DECLARE #values TABLE (ID INT IDENTITY, value NVARCHAR(20))
INSERT INTO #values (value) VALUES
(N'78-22¼'),(N'78-18⅝'),(N'10+1')
;WITH sort AS (
SELECT v.*, t.*,
CASE WHEN m.value = v.value THEN
CASE WHEN t.Dec IS NOT NULL THEN REPLACE(p.value,t.Glyph,'')+dec
ELSE p.value
END
ELSE
CASE WHEN t.Dec IS NOT NULL THEN REPLACE(m.value,t.Glyph,'')+dec
ELSE m.value
END
END AS v,
CASE WHEN m.value = v.value THEN '+'
ELSE '-' END AS op,
ROW_NUMBER() OVER (PARTITION BY v.value ORDER BY CASE WHEN m.value = v.value THEN CHARINDEX(m.value,v.value) ELSE CHARINDEX(p.value,v.value) END) AS subID
FROM #values v
OUTER APPLY STRING_SPLIT(v.value,'-') m
OUTER APPLY STRING_SPLIT(v.value,'+') p
LEFT OUTER JOIN #table t
ON RIGHT(CASE WHEN m.value = v.value THEN p.value ELSE m.value END,1) = t.Glyph
)
SELECT ID, value, SUM(v * CASE WHEN subId = 1 THEN 1 WHEN op = '+' THEN 1 ELSE -1 END) AS v
FROM sort
GROUP BY ID, value
ID value v
---------------------
1 78-22¼ 55.750000
2 78-18⅝ 59.375000
3 10+1 11.000000
#values replaces your table.
disclaimer: this works, it'll probably perform like hot garbage, but it works :P

Answer 3

In T-SQL you could write a function like this that takes a vulgar fraction and replaces it with its decimal equivalent (this is not completely exhaustive, but handles the most common fractions, and makes a guess about whether you want .666 or .667 or something else for ⅔):
CREATE FUNCTION dbo.FractionToDecimal(#str nvarchar(255))
RETURNS TABLE
AS
RETURN
(
SELECT str = REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
REPLACE(REPLACE(REPLACE(REPLACE(#str, N'¼','.25'),
N'½','.5'), N'¾','.75'), N'⅓','.333'), N'⅔','.666'),
N'⅛','.125'), N'⅜','.375'), N'⅝','.625'), N'⅞','.875')
);
Sample usage:
DECLARE #x table(str nvarchar(255));
INSERT #x VALUES(N'78-22¼'),(N'78-18⅝');
SELECT [input] = i.str, [output] = o.str
FROM #x AS i
CROSS APPLY dbo.FractionToDecimal(str) AS o;
Output:
input
output
78-22¼
78-22.25
78-18⅝
78-18.625
Working example in this fiddle.
Note there are only so many fraction codes available that you could be pulling in ... so you could add any to the above e.g. from this set but it isn't the case that you would have to handle any possible fraction, only the ones that are represented by these specific symbols. If someone passes in plain text 9/10 or 31/33 that is a completely different problem space than what you have outlined in the question.