Update SQL Data using mask and rules - sql

Question

I have about 3000 entries in a column in SQL 2012 which are unstructured at the moment ie
1.1.01.10, 1.1.1.11
I want to get the data into a format which includes a leading 0 for all single numbers i.e.
01.01.01.10 and so on.
is there any way of doing this with an update query? I can do this by exporting to excel and manipulating there but I want to avoid this if possible.

Answer 1

Alter function Pad
(
#str varchar(max)
)
returns varchar(max)
as
begin
Declare #nstr varchar(max)
while(PATINDEX('%.%',#str)<>0)
begin
Set #nstr = isnull(#nstr,'')+case when PATINDEX('%.%',#str) = 2 then '0'+substring(#str,PATINDEX('%.%',#str)-1,1) else SUBSTRING(#str,1,PATINDEX('%.%',#str)-1) end+'.'
Set #str = case when PATINDEX('%.%',#str) = 2 then stuff(#str,PATINDEX('%.%',#str)-1,2,'') else stuff(#str,1,PATINDEX('%.%',#str),'') end
end
Set #nstr = isnull(#nstr,'')+case when len(#str) <> 1 then #str when len(#str) = 1 then '0'+#str else '' end
return #nstr
end
update t
set num = [dbo].pad(num)
from table t

Answer 2

If the data have always 4 block it's possible to break them in single unit one at a time.
With F AS (
SELECT data
, rem = substring(data, patindex('%.%', data) + 1, len(data))
, value1 = substring(data, 1, patindex('%.%', data) - 1)
FROM Table1
), S AS (
SELECT data
, rem = substring(rem, patindex('%.%', rem) + 1, len(rem))
, value1
, value2 = substring(rem, 1, patindex('%.%', rem) - 1)
FROM F
), T AS (
SELECT data
, value1
, value2
, value3 = substring(rem, 1, patindex('%.%', rem) - 1)
, value4 = substring(rem, patindex('%.%', rem) + 1, len(rem))
FROM S
)
UPDATE T SET
Data = CONCAT(RIGHT('00' + value1, 2), '.'
, RIGHT('00' + value2, 2), '.'
, RIGHT('00' + value3, 2), '.'
, RIGHT('00' + value4, 2));
SQLFiddle Demo
the query can be made smaller, but losing readability.
If the number of block are unknown and/or can change between rows, the query is more complex and involve a recursive CTE
With Splitter AS (
-- anchor
SELECT data
, rem = substring(data, patindex('%.%', data) + 1, len(data))
, pos = len(data) - len(replace(data, '.', '')) + 1
, value = substring(data, 1, patindex('%.%', data) - 1)
, res = CAST('' as nvarchar(50))
FROM Table1
UNION ALL
-- runner
SELECT data
, rem = substring(rem, patindex('%.%', rem) + 1, len(rem))
, pos = pos - 1
, value = substring(rem, 1, patindex('%.%', rem) - 1)
, res = CAST(res + RIGHT('00' + value, 2) + '.' as nvarchar(50))
FROM Splitter
WHERE patindex('%.%', rem) > 1
UNION ALL
-- stop
SELECT data
, rem = ''
, pos = pos - 1
, value = rem
, res = CAST(res + RIGHT('00' + value, 2)
+ '.' + RIGHT('00' + rem, 2) as nvarchar(50))
FROM Splitter
WHERE patindex('%.%', rem) = 0
AND rem <> ''
)
UPDATE table1 Set
Data = res
FROM table1 t
INNER JOIN Splitter s ON t.Data = s.Data and s.Pos = 1
SQLFiddle demo
The anchor query of the CTE get the first block in value, set pos with the number of block and prepare the result (res).
The runner query works for the following block, but not the last one, searching the nth block and adding blocks to the result.
The stop query get the last block without searching for another dot, that will not find, and complete the constrution of the result. Having set the pos initially to the number of blocks, now it'll be 1.