I am working in SQL Server 2008. I am trying to test whether a string (varchar) has only digit characters (0-9). I know that the IS_NUMERIC function can give spurious results. (My data can possibly have $ signs, which should not pass the test.) So, I'm avoiding that function.
I already have a test to see if a string has any non-digit characters, i.e.,
some_column LIKE '%[^0123456789]%'
I would think that the only-digits test would be something similar, but I'm drawing a blank. Any ideas?
Use Not Like
where some_column NOT LIKE '%[^0-9]%'
Demo
declare #str varchar(50)='50'--'asdarew345'
select 1 where #str NOT LIKE '%[^0-9]%'
There is a system function called ISNUMERIC for SQL 2008 and up. An example:
SELECT myCol
FROM mTable
WHERE ISNUMERIC(myCol)<> 1;
I did a couple of quick tests and also looked further into the docs:
ISNUMERIC returns 1 when the input expression evaluates to a valid numeric data type; otherwise it returns 0.
Which means it is fairly predictable for example
-9879210433 would pass but 987921-0433 does not.
$9879210433 would pass but 9879210$433 does not.
So using this information you can weed out based on the list of valid currency symbols and + & - characters.
Solution:
where some_column NOT LIKE '%[^0-9]%'
Is correct.
Just one important note: Add validation for when the string column = '' (empty string). This scenario will return that '' is a valid number as well.
Method that will work. The way it is used above will not work.
declare #str varchar(50)='79136'
select
case
when #str LIKE replicate('[0-9]',LEN(#str)) then 1
else 0
end
declare #str2 varchar(50)='79D136'
select
case
when #str2 LIKE replicate('[0-9]',LEN(#str)) then 1
else 0
end
DECLARE #x int=1
declare #exit bit=1
WHILE #x<=len('123c') AND #exit=1
BEGIN
IF ascii(SUBSTRING('123c',#x,1)) BETWEEN 48 AND 57
BEGIN
set #x=#x+1
END
ELSE
BEGIN
SET #exit=0
PRINT 'string is not all numeric -:('
END
END
I was attempting to find strings with numbers ONLY, no punctuation or anything else. I finally found an answer that would work here.
Using PATINDEX('%[^0-9]%', some_column) = 0 allowed me to filter out everything but actual number strings.
The selected answer does not work.
declare #str varchar(50)='79D136'
select 1 where #str NOT LIKE '%[^0-9]%'
I don't have a solution but know of this potential pitfall. The same goes if you substitute the letter 'D' for 'E' which is scientific notation.
Related
I have a TBV function. And that function getting couple of input parameters.
CREATE FUNCTION [dbo].[fn]
(
#id NVARCHAR(50),
...
...
)
For example i want to check that #id is not null and is not whitespace.
I was tinking to do like this
SELECT * FROM [FN_Table]() WHERE
COALESCE(#Id,'') !='' AND NULLIF(#id,'') !=null AND #Id=Id
But this is a tedious way i am sure that there would be more elegant and effective way i just newbbe in SQL and do not know best practices.
If you want id to be not null or white space, you can use ltrim():
where ltrim(#id) <> ''
This does the NULL check as well, implicitly.
I'm not sure why you have a comparison to zero. Based on your question this is not necessary. If you are passing in numbers, you should not be using a string type.
Try this, Check with ISNULL and then Get BlankSpace Character Index
SELECT
CASE WHEN ISNULL(#ID,'')='' THEN 1
WHEN CHARINDEX(' ',#ID) >0 THEN 1
ELSE 0
END
I have have been reading up on PATINDEX attempting to understand what and why. I understand the when using the wildcards it will return an INT as to where that character(s) appears/starts. So:
SELECT PATINDEX('%b%', '123b') -- returns 4
However I am looking to see if someone can explain the reason as to why you would use this in a simple(ish) way. I have read some other forums but it just is not sinking in to be honest.
Are you asking for realistic use-cases? I can think of two, real-life use-cases that I've had at work where PATINDEX() was my best option.
I had to import a text-file and parse it for INSERT INTO later on. But these files sometimes had numbers in this format: 00000-59. If you try CAST('00000-59' AS INT) you'll get an error. So I needed code that would parse 00000-59 to -59 but also 00000159 to 159 etc. The - could be anywhere, or it could simply not be there at all. This is what I did:
DECLARE #my_var VARCHAR(255) = '00000-59', #my_int INT
SET #my_var = STUFF(#my_var, 1, PATINDEX('%[^0]%', #my_var)-1, '')
SET #my_int = CAST(#my_var AS INT)
[^0] in this case means "any character that isn't a 0". So PATINDEX() tells me when the 0's end, regardless of whether that's because of a - or a number.
The second use-case I've had was checking whether an IBAN number was correct. In order to do that, any letters in the IBAN need to be changed to a corresponding number (A=10, B=11, etc...). I did something like this (incomplete but you get the idea):
SET #i = PATINDEX('%[^0-9]%', #IBAN)
WHILE #i <> 0 BEGIN
SET #num = UNICODE(SUBSTRING(#IBAN, #i, 1))-55
SET #IBAN = STUFF(#IBAN, #i, 1, CAST(#num AS VARCHAR(2))
SET #i = PATINDEX('%[^0-9]%', #IBAN)
END
So again, I'm not concerned with finding exactly the letter A or B etc. I'm just finding anything that isn't a number and converting it.
PATINDEX is roughly equivalent to CHARINDEX except that it returns the position of a pattern instead of single character. Examples:
Check if a string contains at least one digit:
SELECT PATINDEX('%[0-9]%', 'Hello') -- 0
SELECT PATINDEX('%[0-9]%', 'H3110') -- 2
Extract numeric portion from a string:
SELECT SUBSTRING('12345', PATINDEX('%[0-9]%', '12345'), 100) -- 12345
SELECT SUBSTRING('x2345', PATINDEX('%[0-9]%', 'x2345'), 100) -- 2345
SELECT SUBSTRING('xx345', PATINDEX('%[0-9]%', 'xx345'), 100) -- 345
Quoted from PATINDEX (Transact-SQL)
The following example uses % and _ wildcards to find the position at
which the pattern 'en', followed by any one character and 'ure' starts
in the specified string (index starts at 1):
SELECT PATINDEX('%en_ure%', 'please ensure the door is locked');
Here is the result set.
8
You'd use the PATINDEX function when you want to know at which character position a pattern begins in an expression of a valid text or character data type.
I am using SQL Server 2008
I have sql string in column with ; separated values. How i can trim the below value
Current string:
;145615;1676288;178829;
Output:
145615;1676288;178829;
Please help with sql query to trim the first ; from string
Note : The first char may be or may not be ; but if it is ; then only it should trim.
Edit: What i had tried before, although it doesn't make sense after so many good responses.
DECLARE
#VAL VARCHAR(1000)
BEGIN
SET #VAL =';13342762;1334273;'
IF(CHARINDEX(';',#VAL,1)=1)
BEGIN
SELECT SUBSTRING(#VAL,2,LEN(#VAL))
END
ELSE
BEGIN
SELECT #VAL
END
END
SELECT CASE WHEN col LIKE ';%'
THEN STUFF(col,1,1,'') ELSE col END
FROM dbo.table;
Just check the first character, and if it matches, start from the second character:
SELECT CASE WHEN SUBSTRING(col,1,1) = ';'
THEN SUBSTRING(col,2,LEN(col))
ELSE col
END AS col
Here's an example:
DECLARE #v varchar(10)
SET #v = ';1234'
SELECT
CASE
WHEN LEFT(#v,1) = ';' THEN RIGHT(#v, LEN(#v) - 1)
ELSE #v
END
A further development on #Aaron Bertrand's answer:
SELECT
STUFF(col, 1, PATINDEX(';%', col), '')
FROM ...
PATINDEX is similar to LIKE in that it uses a pattern search, but being a function it also returns the position of the first match. In this case, since we a looking for a ; specifically at the beginning of a string, the position returned is going to be either 1 (if found) or 0 (if not found). If it is 1, the STUFF function will delete 1 character at the beginning of the string, and if the position is 0, STUFF will delete 0 characters.
I have a vairable
DECLARE #AssignOn nvarchar(20)='0,2,5'
I want to check a condition like this
DECLARE #index int
SET DATEFIRST 7
SELECT #index=DATEPART(DW, GETDATE())-1
IF(CONVERT(nvarchar(2),#index) IN #AssignOn)
IN cannot be used here . Any other methods to do this INLINE
You can use CharIndex to find if you have a match. It returns a non zero value if the first string appears in the second.
IF(CHARINDEX(CONVERT(nvarchar(2),#index), #AssignOn) > 0)
The easiest way to do this is to search for the substring ',needle,' in the csv list string. However, this doesn't work correctly for the first and last elements. This can be overcome by concatenating a comma onto each side of the csv list string.
An example in SQL might be:
SELECT
CHARINDEX(','+ NEEDLE +',', ','+ HAYSTACK +',')
FROM table;
Or using LIKE:
SELECT *
FROM table
WHERE ','+ HAYSTACK +',' LIKE '%,'+ NEEDLE +',';
IF CHARINDEX(','+CONVERT(nvarchar(2),#index)+',', ','+#AssignOn+',') <> 0
As you actually define the values in the code you could instead;
DECLARE #AssignOn TABLE (value int)
INSERT #AssignOn VALUES (0),(2),(5)
... #index IN (SELECT value FROM #AssignOn)
how can I accomplish:
select * from table where column_value is int
I know I can probably inner join to the system tables and type tables but I'm wondering if there's a more elegant way.
Note that column_value is a varchar that "could" have an int, but not necessarily.
Maybe I can just cast it and trap the error? But again, that seems like a hack.
select * from table
where column_value not like '[^0-9]'
If negative ints are allowed, you need something like
where column_value like '[+-]%'
and substring(column_value,patindex('[+-]',substring(column_value,1))+1,len(column_value))
not like '[^0-9]'
You need more code if column_value can be an integer that exceeds the limits of the "int" type, and you want to exclude such cases.
Here if you want to implement your custom function
CREATE Function dbo.IsInteger(#Value VARCHAR(18))
RETURNS BIT
AS
BEGIN
RETURN ISNULL(
(SELECT CASE WHEN CHARINDEX('.', #Value) > 0 THEN
CASE WHEN CONVERT(int, PARSENAME(#Value, 1)) <> 0 THEN 0 ELSE 1 END
ELSE 1
END
WHERE ISNUMERIC(#Value + 'e0') = 1), 0)
END
ISNUMERIC returns 1 when the input
expression evaluates to a valid
integer, floating point number, money
or decimal type; otherwise it returns
0. A return value of 1 guarantees that expression can be converted to one of
these numeric types.
I would do a UDF as Svetlozar Angelov suggests, but I would check for ISNUMERIC first (and return 0 if not), and then check for column_value % 1 = 0 to see if it's an integer.
Here's what the body might look like. You have to put the modulo logic in a separate branch because it will throw an exception if the value isn't numeric.
DECLARE #RV BIT
IF ISNUMERIC(#value) BEGIN
IF CAST(#value AS NUMERIC) % 1 = 0 SET #RV = 1
ELSE SET #RV = 0
END
ELSE SET #RV = 0
RETURN #RV
This should handle all cases without throwing any exceptions:
--This handles dollar-signs, commas, decimal-points, and values too big or small,
-- all while safely returning an int.
DECLARE #IntString as VarChar(50) = '$1,000.'
SELECT CAST((CASE WHEN --This IsNumeric check here does most of the heavy lifting. The rest is Integer-Specific
ISNUMERIC(#IntString) = 1
--Only allow Int-related characters. This will exclude things like 'e' and other foreign currency characters.
AND #IntString NOT LIKE '%[^ $,.\-+0-9]%' ESCAPE '\'--'
--Checks that the value is not out of bounds for an Integer.
AND CAST(REPLACE(REPLACE(#IntString,'$',''),',','') as Decimal(38)) BETWEEN -2147483648 AND 2147483647
--This allows values with decimal-points for count as an Int, so long as there it is not a fractional value.
AND CAST(REPLACE(REPLACE(#IntString,'$',''),',','') as Decimal(38)) = CAST(REPLACE(REPLACE(#IntString,'$',''),',','') as Decimal(38,2))
--This will safely convert values with decimal points to casting later as an Int.
THEN CAST(REPLACE(REPLACE(#IntString,'$',''),',','') as Decimal(10))
END) as Int)[Integer]
Throw this into a Scalar UDF and call it ReturnInt().
If the value comes back as NULL, then it's not an int (so there's your IsInteger() requirement)
If you don't like typing "WHERE ReturnInt(SomeValue) IS NOT NULL", you could throw it into another scalar UDF called IsInt() to call this function and simply return "ReturnInt(SomeValue) IS NOT NULL".
The cool thing is, the UDF can serve double duty by returning the "safely" converted int value.
Just because something can be an int doesn't mean casting it as an int won't throw a huge exception. This takes care of that for you.
Also, I'd avoid the other solutions because this universal approach will handle commas, decimals, dollar signs, and checks the acceptable Int value's range while the other solutions do not - or they require multiple SET operations that prevent you from using the logic in a Scalar-Function for maximum performance.
See the examples below and test them against my code and others:
--Proves that appending "e0" or ".0e0" is NOT a good idea.
select ISNUMERIC('$1' + 'e0')--Returns: 0.
select ISNUMERIC('1,000' + 'e0')--Returns: 0.
select ISNUMERIC('1.0' + '.0e0')--Returns: 0.
--While these are numeric, they WILL break your code
-- if you try to cast them directly as int.
select ISNUMERIC('1,000')--Returns: 1.
select CAST('1,000' as Int)--Will throw exception.
select ISNUMERIC('$1')--Returns: 1.
select CAST('$1' as Int)--Will throw exception.
select ISNUMERIC('10.0')--Returns: 1.
select CAST('10.0' as Int)--Will throw exception.
select ISNUMERIC('9999999999223372036854775807')--Returns: 1. This is why I use Decimal(38) as Decimal defaults to Decimal(18).
select CAST('9999999999223372036854775807' as Int)--Will throw exception.
Update:
I read a comment here that you want to be able to parse a value like '123.' into an Integer. I have updated my code to handle this as well.
Note: This converts "1.0", but returns null on "1.9".
If you want to allow for rounding, then tweak the logic in the "THEN" clause to add Round() like so:
ROUND(CAST(REPLACE(REPLACE(#IntString,'$',''),',','') as Decimal(10)), 0)
You must also remove the "AND" that checks for "decimal-points" to allow for Rounding or Truncation.
Why not use the following and test for 1?
DECLARE #TestValue nvarchar(MAX)
SET #TestValue = '1.04343234e5'
SELECT CASE WHEN ISNUMERIC(#TestValue) = 1
THEN CASE WHEN ROUND(#TestValue,0,1) = #TestValue
THEN 1
ELSE 0
END
ELSE null
END AS Analysis
If you are purely looking to verify a string is all digits and not just CAST-able to INT you can do this terrible, terrible thing:
select LEN(
REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE(
'-1.223344556677889900e-1'
,'0','') ,'1','') ,'2','') ,'3','') ,'4','') ,'5','') ,'6','') ,'7','') ,'8','') ,'9','')
)
It returns 0 when the string was empty or pure digits.
To make it a useful check for "poor-man's" Integer you'd have to deal with empty string, and an initial negative sign. And manually make sure it isn't too long for your variety of INTEGER.