Ошибка при преобразовании типа данных varchar к float sql

Sometimes, under certain circumstances, when you develop in SQL Server and especially when you try to convert a string data type value to a float data type value, you might get the error message: error converting data type varchar to float. As the error message describes, there is a conversion error and this is most probably due to the input parameter value you used in the conversion function.

Read more below on how you can easily resolve this problem.

Reproducing the Data Type Conversion Error

As mentioned above, the actual reason you get this error message, is that you are passing as a parameter to the CAST or CONVERT SQL Server functions, a value (varchar expression) that is invalid and cannot be converted to the desired data type.

Consider the following example:

-----------------------------------------
--Variable declaration and initialization
-----------------------------------------
DECLARE @value AS VARCHAR(50);

SET @value = '12.340.111,91';

--Perform the casting
SELECT CAST(@value AS FLOAT);

--or
--Perform the conversion
SELECT CONVERT(FLOAT, @value);
-----------------------------------------

If you execute the above code you will get an error message in the following type:

Msg 8114, Level 16, State 5, Line 6
Error converting data type varchar to float.

Another similar example where you get the same data type conversion error, is the below:

-----------------------------------------
--Variable declaration and initialization
-----------------------------------------
DECLARE @value2 AS VARCHAR(50);

SET @value2 = '12,340.15';

--Perform the casting
SELECT CAST(@value2 AS FLOAT);

--or
--Perform the conversion
SELECT CONVERT(FLOAT, @value2);

Why you get this Conversion Error

The exact reason for getting the error message in this case is that you are using the comma (,) as a decimal point and also the dots as group digit symbols. Though SQL Server considers as a decimal point the dot (.). Also when converting a varchar to float you must not use any digit grouping symbols.

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How to Resolve the Conversion Issue

In order for the above code to execute, you would need to first remove the dots (that is the digit grouping symbols in this case) and then replace the comma with a dot thus properly defining the decimal symbol for the varchar expression.

Note: You need to be careful at this point, in order to correctly specify the decimal symbol at the correct position of the number.

Therefore, you can modify the code of example 1 as per below example:

-------------------------------------------
--Variable declaration and initialization
-------------------------------------------
DECLARE @value AS VARCHAR(50);

SET @value = '12.340.111,91';

--Prepare the string for casting/conversion to float
SET @value = REPLACE(@value, '.', '');
SET @value = REPLACE(@value, ',', '.');

--Perform the casting
SELECT CAST(@value AS FLOAT);

--or
--Perform the conversion
SELECT CONVERT(FLOAT, @value);
-----------------------------------------

If you execute the above code you will be able to get the string successfully converted to float.

Similarly, you can modify the code of example 2 as per below example:

-----------------------------------------
--Variable declaration and initialization
-----------------------------------------
DECLARE @value2 AS VARCHAR(50);

SET @value2 = '12,340.15';

--Prepare the string for casting/conversion to float
SET @value2 = REPLACE(@value2, ',', '');

--Perform the casting
SELECT CAST(@value2 AS FLOAT);

--or
--Perform the conversion
SELECT CONVERT(FLOAT, @value2);

Again, if you execute the above code you will be able to get the string successfully converted to float.

*Note: Even though you can try changing the regional settings of the PC for setting the dot (.) as the decimal symbol, this will only affect the way the data is presented to you when returned from the casting/conversion call. Therefore, you still have to modify the varchar expression prior to the casting/conversion operation.

Regarding the message: error converting data type varchar to numeric

The above error message is similar to the one we examined in this article, therefore, the way for resolving the issue is similar to the one we described in the article. The only different for the numeric case, is that you will have to replace FLOAT with numeric[ (p[ ,s] )]. Learn more about the numeric data type in SQL Server and how to resolve the above conversion issue, by reading the relevant article on SQLNetHub.

Watch the Live Demonstration on the VARCHAR to FLOAT Data Type Conversion Error

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How to resolve the error: Error converting data type varchar to float

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Views: 25,686

Вопрос:

When cust_trendd_w_costsv.terms_code like '%[%]%' and (prod.dbo.BTYS2012.average_days_pay) - (substring(cust_trendd_w_costsv.terms_code,3,2)) <= 5 THEN prod.dbo.cust_trendd_w_costsv.terms_code

Лучший ответ:

When cust_trendd_w_costsv.terms_code like '%[%]%' 
and (prod.dbo.BTYS2012.average_days_pay) - 

(case when isnumeric(substring(cust_trendd_w_costsv.terms_code,3,2))=1 
         then cast(substring(cust_trendd_w_costsv.terms_code,3,2) as float)
         else 0
 end)
<= 5 THEN prod.dbo.cust_trendd_w_costsv.terms_code

Ответ №1

select CONVERT(float,'12.5%')

CONVERT(float,REPLACE(terms_code,'%',''))

Ответ №2

 .....and (prod.dbo.BTYS2012.average_days_pay) - (CAST(substring(cust_trendd_w_costsv.terms_code,3,2)) as float ) <= 5 ....

The STR() function accepts a float datatype as the first argument, therefore SQL Server is implicitly converting whatever you pass to this function, which in your case is the CHAR(20) column. Since unknown can’t be converted to a float, you get the error.
If you run the following with the actual execution plan enabled:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL);

SELECT Result = ISNULL(STR(Col, 25, 0), 'Missing')
FROM @T

Then checkthe execution plan XML you will see the implicit conversion:

<ScalarOperator ScalarString="isnull(str(CONVERT_IMPLICIT(float(53),[Col],0),(25),(0)),'Missing')">

The simplest solution is probably to use a case expression and not bother with any conversion at all (only if you know you will only have the 5 values you listed:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL), ('0'), ('50'), ('100');--, ('Unknown');

SELECT Result = CASE WHEN Col IS NULL OR Col = 'Unknown' THEN 'Missing' ELSE Col END
FROM @T;

Result
---------
Missing
0                   
50                  
100                 
Missing             

If you really want the STR() function, you can make the conversion explicit, but use TRY_CONVERT() so that anything that is not a float simply returns NULL:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL), ('0'), ('50'), ('100');--, ('Unknown');

SELECT Result = ISNULL(STR(TRY_CONVERT(FLOAT, Col), 25, 0), 'Missing')
FROM @T

Result
------------
Missing
        0   
       50
      100
Missing

Although, since you the numbers you have stated are integers, I would be inclined to convert them to integers rather than floats:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL), ('0'), ('50'), ('100'), ('Unknown');

SELECT Result = ISNULL(CONVERT(VARCHAR(10), TRY_CONVERT(INT, Col)), 'Missing')
FROM @T;

Result
---------
Missing
0                   
50                  
100                 
Missing      

The STR() function accepts a float datatype as the first argument, therefore SQL Server is implicitly converting whatever you pass to this function, which in your case is the CHAR(20) column. Since unknown can’t be converted to a float, you get the error.
If you run the following with the actual execution plan enabled:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL);

SELECT Result = ISNULL(STR(Col, 25, 0), 'Missing')
FROM @T

Then checkthe execution plan XML you will see the implicit conversion:

<ScalarOperator ScalarString="isnull(str(CONVERT_IMPLICIT(float(53),[Col],0),(25),(0)),'Missing')">

The simplest solution is probably to use a case expression and not bother with any conversion at all (only if you know you will only have the 5 values you listed:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL), ('0'), ('50'), ('100');--, ('Unknown');

SELECT Result = CASE WHEN Col IS NULL OR Col = 'Unknown' THEN 'Missing' ELSE Col END
FROM @T;

Result
---------
Missing
0                   
50                  
100                 
Missing             

If you really want the STR() function, you can make the conversion explicit, but use TRY_CONVERT() so that anything that is not a float simply returns NULL:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL), ('0'), ('50'), ('100');--, ('Unknown');

SELECT Result = ISNULL(STR(TRY_CONVERT(FLOAT, Col), 25, 0), 'Missing')
FROM @T

Result
------------
Missing
        0   
       50
      100
Missing

Although, since you the numbers you have stated are integers, I would be inclined to convert them to integers rather than floats:

DECLARE @T TABLE (Col CHAR(20));
INSERT @T VALUES (NULL), ('0'), ('50'), ('100'), ('Unknown');

SELECT Result = ISNULL(CONVERT(VARCHAR(10), TRY_CONVERT(INT, Col)), 'Missing')
FROM @T;

Result
---------
Missing
0                   
50                  
100                 
Missing      

CASE
WHEN (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))> 0 AND (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))<=0.25 THEN (0.25+FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))

WHEN (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))> 0.25 AND (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))<=0.50 THEN (0.50+FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))

WHEN (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))> 0.50 AND (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))<=0.75 THEN (0.75+FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))

WHEN (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))> 0.75 AND (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))<1 THEN (1+FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))


WHEN (Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)- FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))= 0 THEN (0+FLOOR(Cast(CONVERT(DECIMAL(10,2),(totaleffort/7.40)) as nvarchar)))

END

AS Estimated_Effort_Days,

Приведенный выше код в настоящее время округляет поле с именем totaleffort до ближайшего 25, например, если у меня значение 78.19, оно будет округлено до 78.25.

У меня есть новое требование для значения нуля, когда значение = 0, тогда мне нужно отобразить текст «неизвестный номер». Я попытался добавить дополнительный оператор case, однако запрос не выполняется с ошибкой:

Ошибка преобразования типа данных varchar в float.

Есть ли у кого-нибудь рекомендации для меня?