Does the SQL CASE statement treat variables differently from columns? - sql

I have the following code in a stored procedure and am trying to conditionally format a calculated number based on its length (if the number is less than 4 digits, pad with leading zeros). However, my case statement is not working. The "formattedNumber2" result is the one I'm looking for.
I'm assuming the case statement treats the variable strangely, but I also don't know of a way around this.
DECLARE #Number int = 5
SELECT
CASE
WHEN (LEN(CONVERT(VARCHAR, #Number)) > 4)
THEN #Number
ELSE RIGHT('0000' + CAST(#Number AS VARCHAR(4)), 4)
END AS formattedNumber,
LEN(CONVERT(VARCHAR, #Number)) AS numberLength,
RIGHT('0000' + CAST(#Number AS VARCHAR(4)), 4) AS formattedNumber2
I get the following results when I run the query:
formattedNumber numberLength formattedNumber2
-------------------------------------------------
5 1 0005

SQL DEMO
The problem is you are using different data type on your case , integer and string. So the CASE stay with the first type he find and convert the rest.
CASE WHEN (LEN(convert(VARCHAR, #Number)) > 4) THEN convert(VARCHAR, #Number)

This can be done a lot easier with format() since version 2012.
format(n,
'0000')
And that would also handle negative values, which your current approach apparently doesn't.
Prior 2012 it can be handled with basically replicate() and + (string concatenation).
isnull(replicate('-',
-sign(n)), '')
+
isnull(replicate('0',
4
-
len(cast(abs(n) AS varchar(10)))
),
'')
+
cast(abs(n) AS varchar(10))
(It targets integer values, choose a larger length for the varchar casts for bigint.)
db<>fiddle

Related

CAST(somenumber as VARCHAR(10)) + somestring returns Error converting data type varchar to numeric

I'm trying to combine a min and max salary with a hyphen for display in a report. I feel like I've done this a hundred times but I still can't figure out why I'm getting the "Error converting data type varchar to numeric" especially since I'm trying to convert a numeric to varchar not the other way around.
amt_exp_formatted = CASE
WHEN a.class_code IN ('9997','9998','9999') THEN 0
--ELSE CAST(e.min_sal as VARCHAR(10)) + '-' + CAST(e.max_sal as VARCHAR(10))
ELSE CONVERT(VARCHAR(1), 1) + CONVERT(VARCHAR(1), 'a')
END
In the above example if I use 'a' I get the error. If I change 'a' to '9' then it works AND it appends 9 to the 1 (i.e. 19) rather than adding them together which is exactly what I want but with a character string. I've tried both CAST and CONVERT with no luck. I know I shouldn't need the second CONVERT on the letter 'a' but I was just trying to force the data types to be the same just in case. I have no doubt at all I'm missing something simple but I can't seem to get it so I figured it wouldn't hurt to ask the community.
Thank you!
A case expression returns one value with a determinate type. If any returned fork returns a number, then number it is. And strings get converted.
So, be sure you are returning a string in all cases:
(CASE WHEN a.class_code IN ('9997', '9998', '9999')
THEN '0'
ELSE CONCAT(e.min_sal, '-', e.max_sal)
END)
CONCAT() automatically converts the arguments to strings.
This is becuase you are mixing the data type. in the first part of case you were returning 0 while in the else part you're converting it to varchar(). - you can try the below returning 0 as also varchar
amt_exp_formatted = CASE
WHEN a.class_code IN ('9997','9998','9999') THEN '0'
--ELSE CAST(e.min_sal as VARCHAR(10)) + '-' + CAST(e.max_sal as VARCHAR(10))
ELSE CONVERT(VARCHAR(1), 1) + CONVERT(VARCHAR(1), 'a')
END

Conversion failed from VARCHAR to INT

I am trying to use SQL to get new policy number based on the existing one. I don't want to use update since I don't want to permanently change the records.
My policy numbers are like PFA991228-01 and I want to use SQL to modify and get PFA991228-02. So I am just updating the last 2 digits from 00 to 01 or from 05 to 06 etc. Right now I am getting error for converting varchar to int.
I am new to SQL so not sure if I can just achieve it in my first select statement instead of using sub-query
select
left(p.policynum, 9)
+ '-'
+ right('00' + convert(varchar(255), right(p.policynum, 2) + 1), 2) as newPolicy
From Company55.dbo.policy p
where p.policynum not like '%S%'
I would suggest this logic:
select (left(p.policynum, 9) + '-' +
right( '00' + try_convert(int, right(p.policynum, 2)) + 1 as varchar(255)), 2) as newPolicy
From Company55.dbo.policy P
where p.policynum not like '%S%' and
p.policynum like '%[0-9][0-9]';
Notes:
The where ensures that the output rows all end in two digits.
The try_convert() ensures that the conversion to integer succeeds -- the where is not enough.
This works for both 1- and 2- digit suffixes.
I see no reason for the subquery. right(p.policynum, 2) isn't really that much more complicated than term, for instance.

SQL String Manipulation and character replacement

I have a database with a list of old ItemID's that need updating to a new format.
The old format is of the form 8046Y and the new format moves the 4th digit to the end and prepends a hyphen and adds a 0 if it's a single digit. The old format also uses alpha characters when the number goes over 9 for example 464HB where the H represents 17. I also need to add a 1 to the beginning of the new format. All this can be done with string manipulation in SQL I hope.
Some examples:
8046Y becomes 1804Y-06
464HB becomes 1464B-17 (H = 17)
Can anyone give me some pointers as to how to go about this in SQL?
I got as far as:
select '1' + LEFT(ItemID, 3) + RIGHT(ItemID,1) + '-' + '0' + SUBSTRING(ItemID,3,1) from items
But the conversion from a=10 to z=36 stumped me
Try this:
select
'1'
+ left(#str,3)
+ right(#str,1)
+ '-'
+ case
when substring(#str,4,1) like '%[0-9]%' 1 then right('00' + substring(#str,4,1),2)
else cast(10 + ascii(substring(#str,4,1))-ascii('A') as varchar(2))
end
Explanation: If the 4th character is a digit, then do not change the value and append it after padding with a zero. Otherwise, use ASCII to get the ASCII value for that character, get it's difference with the value for 'A' and add the offset of 10.
Demo
Since I don't know if there are any other special character to consider except 'H' only included this single character.
DECLARE #val CHAR(5) = '464HB'
SELECT #val, '1' + LEFT(#val,3)+SUBSTRING(#val,5,1)+'-'+CASE WHEN +SUBSTRING(#val,4,1)='H' THEN '17' ELSE '0'+SUBSTRING(#val,4,1) END
select '1' + LEFT(ItemID, 3) + RIGHT(ItemID,1) + '-'
+CASE RIGHT(LEFT(ItemID,1),2)
WHEN 'a' then 10
WHEN 'b' THEN 11
etc...
END [NewItemID]
from items
Just add the appropriate cases in that format.
I do it only for the challenge, i dont recommend to use
DECLARE #id varchar(5) = '8046Y'
--SET #id = '464HB'
SELECT
'1' +
LEFT(#id, 3) +
RIGHT(#id, 1) +
'-' +
CASE WHEN ISNUMERIC(RIGHT(LEFT(#id, 4), 1)) = 1 THEN
RIGHT(LEFT(#id, 4), 1)
ELSE
RIGHT('00' + CONVERT(VARCHAR, ASCII(RIGHT(LEFT(#id, 4), 1)) - 64 + 9), 2)
END
-64 for the Start of ASCII A and +9 for your convention
Personally, I'd create a function for it.
Create a variable to handle the new value.
Manipulate the positions through SUBSTRING, you can also use RIGHT or LEFT
When adding zeros in single digit numbers, just do conditional statement
Regarding the conversion of letters to numbers(e.g. letter H), the converted value of the first letter is 65 assuming it's all capital. So, A=65, B=66, H=72 and so on. Use this data in manipulating the values. Uhm, I'll give you my thoughts but you can optimize it (since I don't have lots of time).
Taking your example of H=17, so A=10. Just subtract 55 in the conversions. So H=72(-55) becomes 17. This is applicable to all letters (in uppercase only).
I think this much is more than enough to guide you. Hope this would help.

Remove trailing zero from decimal number

I have a one database table field called Amount which type is decimal(18,6). so it is stored in database up to 6 decimal points like 9.786534 But while retrieving that field using select query i have to take care like following
Remove trialling zero e.g if number is 9.230000 then result is only 9.23
If decimal points are all zero then only remove only four trialling zero e.g If number is 9.000000 then result is 9.00
Result is up to 2 decimal point if there are trialling zero.
If we write simple query like
select TOP 1 Amount From EmployeeMaster
then it gives 9.230000
but my intension is to remove trailing zero..
Please help me..
It works for removing trailing zeros, but I am still not able to convert 9 to 9.00 in this method.
Declare #myvalue varchar(50),
#Price Varchar(50)
Set #Price = '9.230000'
set #Myvalue = reverse(substring(#Price,patindex('%.%',#Price)+1,len(#Price)))
SELECT
case
When patindex('%.%[1-9]%',#price) = 0 Then
substring(#price,1,patindex('%.%',#price)-1)
else
substring(#price,1,patindex('%.%',#price)-1) + '.' + Reverse(substring(#Myvalue,patindex('%[1-9]%',#Myvalue),len(#Myvalue)))
END
Coming from decimal(18,6) you could do...
select cast(Amount as decimal(18,2))
Most databases that support the CAST function will round the number while converting it. On SQLServer this is what I would do if I wanted rounding.
If what you actually want is a string with only two digits after the decimal then you could
select cast((Amount as decimal(18,2)) as nvarchar)
nvarchar is SQLServer's variable length unicode type. Databases do not agree much on string types. Your database may have a different one. The rest of that sql is ANSI standard. Not all dbs support that either but many do.
This should work
SELECT CAST(REPLACE(RTRIM(REPLACE(CAST(CAST(33.9082976 AS DECIMAL(38,8)) AS NVARCHAR(256)),'0',' ')),' ','0') AS FLOAT)
Does this work?
select TOP 1 ROUND(Amount, 2) From EmployeeMaster
TRY below mentioned code.
SELECT TOP 1 CONVERT(DECIMAL(10,2),Amount) From EmployeeMaster
Hope it will work as expected.
An alternative approach:
1) convert the decimal to a string;
2) split the string into 2 parts, separating the last 4 characters from the rest of the string;
3) remove trailing zeros from the last 4 characters;
4) concatenate the two parts back.
WITH data (V) AS (SELECT CAST(9.786534 AS decimal(18,6))
UNION ALL
SELECT CAST(9.78653 AS decimal(18,6))
UNION ALL
SELECT CAST(9.7800 AS decimal(18,6))
UNION ALL
SELECT CAST(9.7 AS decimal(18,6))
UNION ALL
SELECT CAST(9.00000 AS decimal(18,6))
)
, AsString (V) AS (SELECT CAST(V AS varchar) FROM data)
, Split (L, R) AS (SELECT LEFT(V, LEN(V) - 4), RIGHT(V, 4) FROM AsString)
, Adjusted AS (SELECT L,
REPLACE(RTRIM(REPLACE(R, '0', ' ')), ' ', '0') AS R
FROM Split)
SELECT Result = L + R FROM Adjusted
The output of the above script is:
Result
--------
9.786534
9.78653
9.78
9.70
9.00
I guess using patindex in your case:
CASE WHEN FLOOR(Amount) <> CEILING(Amount) THEN
LTRIM(SUBSTRING(STR(Amount, 18, 6), 1, LEN(STR(Amount, 18, 6)) - PATINDEX('%[^0]%', REVERSE(str(Amount, 18, 6))) + 1))
ELSE STR(Amount,18,2)
END
for a decimal(18,6) field this should work:
select trim(to_char(Amount, '999999999999999999.99')) from EmployeeMaster
(at least for Oracle, not sure about other types)

Most efficient method for adding leading 0's to an int in sql

I need to return two fields from a database concatenated as 'field1-field2'. The second field is an int, but needs to be returned as a fixed length of 5 with leading 0's. The method i'm using is:
SELECT Field1 + '-' + RIGHT('0000' + CAST(Field2 AS varchar),5) FROM ...
Is there a more efficient way to do this?
That is pretty much the way: Adding Leading Zeros To Integer Values
So, to save following the link, the query looks like this, where #Numbers is the table and Num is the column:
SELECT RIGHT('000000000' + CONVERT(VARCHAR(8),Num), 8) FROM #Numbers
for negative or positive values
declare #v varchar(6)
select #v = -5
SELECT case when #v < 0
then '-' else '' end + RIGHT('00000' + replace(#v,'-',''), 5)
Another way (without CAST or CONVERT):
SELECT RIGHT(REPLACE(STR(#NUM),' ','0'),5)
If you can afford/want to have a function in your database you could use something like:
CREATE FUNCTION LEFTPAD
(#SourceString VARCHAR(MAX),
#FinalLength INT,
#PadChar CHAR(1))
RETURNS VARCHAR(MAX)
AS
BEGIN
RETURN
(SELECT Replicate(#PadChar, #FinalLength - Len(#SourceString)) + #SourceString)
END
I would do it like this.
SELECT RIGHT(REPLICATE('0', 5) + CAST(Field2 AS VARCHAR(5),5)
Not necessarily all that "Easier", or more efficient, but better to read. Could be optimized to remove the need for "RIGHT"
If you want to get a consistent number of total strings in the final result by adding different number of zeros, here is a little bit modification (for vsql)
SELECT
CONCAT(
REPEAT('0', 9-length(TO_CHAR(var1))),
CAST(var1 AS VARCHAR(9))
) as var1
You can replace 9 by any number for your need!
BRD