MSSQL([varcharColumn] to int) to SELECT conversion is performed before the WHERE clause filters out incorrect values
First of all, this is not an "obvious design issue". SQL is a language that describes output, not a procedural language that specifies how the processing is done. There is usually no guarantee of order processing, and this is an advantage. You could say there's a design problem, but it boils down to general exception handling in SQL statements.
According to the SQL Server documentation (http://msdn.microsoft.com/en-us/library/ms181765.aspx), it may depend on the order of evaluation of a CASE statementfor scalar expressions. Then the following should work:
select (caso quando isnumeric(c.varcharColumn) = 1 luego cast(c.varcharColumn as int) end)
Or, to expand an "int" expression:
select (if isnumeric(c.varcharColumn) = 1 and c.varcharColumn not like '%.%' and c.varcharColumn not like '%e%'
então cast(c.varcharColumn als int)
fin)
At least your code does an explicit CAST. This situation is much worse when the conversions are implicit (and there are hundreds of columns).
Why does a sudden query plan change appear to break a query?
Because filters and expressions can be evaluated in a different order (for example, before or after filtering the values to be broken). To make this simpler, imagine you're a barber with a lobby full of customers:
- Cut an inch of each client's hair
- Filter bald head
contra
- Filter bald head
- cut an inch of hair off theremainingcustomers
A simpler example in SQL Server is:
- Get month name from string
- Filter strings that are not valid data
contra
- Filter strings that are not valid data
- Get month name from remaining strings which are valid dates
One way around this in SQL Server is to use aCAIRExpression to only evaluate the lines that don't wrap the expression (or in this example, change the expression to not break):
subcadena(ext_inv_ref, 1, len(ext_inv_ref) - CASO
CUANDO len(ext_inv_ref) >= 3 THEN 3 ELSE 0 END)
In plain language this just means that the rightmost 3 characters should be removed, butOnlyif the string already has at least 3 characters.
or you can useCONNECTION/NULIFor a variety of other methods, depending on whether you want an empty string or NULL if the input is < 3 characters.
Some other questions for more information:
- Understand why my CAST to INT is not working
- Why would YEAR fail with a date conversion error?
- MSSQL([varcharColumn] to int) to SELECT conversion is performed before the WHERE clause filters out incorrect values
- Conversion failed when converting date and/or time from a string. sql query
- Invalid length parameter passed to left function or substring: error does not occur consistently for same data
CAST to int used with LEFT on an nvarchar field not working correctly?
I can see it
You will see 'A/P in' in your stats. Character '/' cannot be converted to INT
MSSQL([varcharColumn] to int) to SELECT conversion is performed before the WHERE clause filters out incorrect values
In short, you want to do the following:
select(case when isnumeric(TO.LineMemo) = 1 then cast(TO.LineMemo as int) end)
Why would YEAR fail with a date conversion error?
I accept itRValoresIt's some kind of string column for some reason. You need to fix this and store date data with a date data type (obviously in a separate column of this mixed bag).
If you can't fix this, you can avoid what Damien described above:
CASE WHEN DATE(Valores RV) = 1 THEN CONVERT(Datum, Valores RV) ENDS AS DateSignature
(What the "date" will doNULLif SQL Server can't figure out how to convert it to a date).
You cannot get around this by simply adding aOSclause, because SQL Server usually tries to do the conversion on theSELECTList before filtering (it all depends on the plan). Also, you cannot force the order of operations using a subquery, CTE, union order hints, etc. There is an open connection point on this thread - they are "aware" and "hope to address it in a future release". ."
In the absence of a CASE expression that forces SQL Server to evaluate the ISDATE() result before trying to convert (as long as there are no aggregations on any branches), you can:
- Store the filtered results in a #temp table, then select #temp from that table and just apply the transform.
- Just return the string and treat it like a date on the client and extract the YEAR/MONTH parts and so on.
- Just use string manipulation to extract YEAR=LEFT(col, 4) etc.
use
TRY_CONVERT()since I noticed you are on SQL Server 2012:TRY_CONVERT(FECHA, RWerte) AS FechaFirma
Does converting to datetime fail only in the WHERE clause?
When the cast is in the WHERE clause, it can evaluate many more records (values) than if it appeared in the projection list. I already talked about this in another context, see that the T-SQL functions do not imply a specific order of execution and the short circuit of the boolean operator in SQL Server. Your case is even simpler, but it's similar, and ultimately the root cause is the same: don't assume a mandatory execution order when working with a declarative language like SQL.
Your best solution by far is to clean up the data and change the column type to a DATETIME or DATETIME2 type.noOther solutions will have a flaw or two, so you better do it right.
To update
After looking closer (sorry I'm @VLDB and only looking at SO between sessions) I see that it has EAV storage with inherently untyped semantics (theAttributecan be a string, a date, an int, etc.). My opinion is that the best you can do is usevariante_sqlin the warehouse and up to the customer (e.g. projectvariante_sql). You can bind the type to the client, all client APIs have methods to extract the internal type of avariante_sql, see Using sql_variant data (well, almost every client API... Using sql_variant data type in CLR). withvariante_sqlYou can store multiple types without iteration issues in a string representation that you can useSQL_VARIANT_PROPIEDADinspect things likebasic typeon stored values and can even do things like check constraints to enforce data type correctness.
SQL Server: Compare ordered columns from multiple tables
As long as the item names are consistent over the years, you just need to join the other tables
with count as (
select e.ItemName, e.ItemCount, row_number() over (partition by order of e.ItemName by conversion (e.ItemCount as int) desc) as rk
from Table2015 and where e.ItemCount <> 'X')select s.ItemName
and item count
, CASE WHEN CAST(t15.ItemCount AS INT) > ISNULL(CAST(t14.ItemCount AS INT), 0) THEN 1 OUTRO 0 TERMINA COMO GreaterThan2014
, CASE WHEN CAST(t15.ItemCount AS INT) > ISNULL(CAST(t13.ItemCount AS INT), 0) THEN 1 OUTRO 0 TERMINA COMO GreaterThan2013
of counts
inner join count t15 ON s.ItemName = t15.ItemName and t15.rk = 1
connect left (
Auswahl ItemName, MAX(CASE WHEN IsNumeric(ItemCount) = 1 THEN CAST(ItemCount AS INT) ELSE -1 END)
da tabela2014
onde ItemCount <> 'X'
Group by ItemName
) t14 de s.ItemName = t14.ItemName
connect left (
Auswahl ItemName, MAX(CASE WHEN IsNumeric(ItemCount) = 1 THEN CAST(ItemCount AS INT) ELSE -1 END)
da Tabela2013
onde ItemCount <> 'X'
Group by ItemName
) t13 de s.ItemName = t13.ItemName
donde s.rk <4
sort by s.ItemName,s.rk;
(Video) Sorting in SQL | ORDER BY | Sorting Interview Q&A | Varchar to Int| Varchar to Date | CAST| ConvertAlso, you really shouldn't have one.'X'as a possibility in a counting field. When you count something, it should be written as aE T.
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FAQs
How to convert varchar column to int in SQL? ›
SQL Server's CAST() and CONVERT() methods can be used to convert VARCHAR to INT.
How to fix error converting data type varchar to numeric in SQL? ›Solution 1
To fix this, you'd need to make sure you provide a value that SQL Server can convert. If you're passing a column, check that you've got the right column. Same if you're passing a variable – check that it's the right variable.
To convert a varchar type to a numeric type, change the target type as numeric or BIGNUMERIC as shown in the example below: SELECT CAST('344' AS NUMERIC) AS NUMERIC; SELECT CAST('344' AS BIGNUMERIC) AS big_numeric; The queries above should return the specified value converted to numeric and big numeric.
How to convert varchar variable to int in SQL Server? ›It converts varchar to int type with the help of cast and convert functions. The varchar variable must contain numeric characters. SELECT CAST('77788' AS INT); SELECT CAST(CAST ('888.67' AS NUMERIC) AS INT);
How do I fix conversion failed when converting the varchar value to data type int? ›To fix this, either convert the number to a string, or use a function like CONCAT() or CONCAT_WS() to perform the concatenation.
How do I cast a column to an int? ›Convert Column to int (Integer)
Use pandas DataFrame. astype() function to convert column to int (integer), you can apply this on a specific column or on an entire DataFrame. To cast the data type to 64-bit signed integer, you can use numpy. int64 , numpy.
A VARCHAR declaration must include a positive integer in parentheses to define the maximum allowable character string length. For example, VARCHAR(n) can accept any length of character string up to n characters in length.
What can I use instead of varchar in SQL? ›1. CHAR Datatype: It is a datatype in SQL which is used to store character string of fixed length specified.
What function would you use to convert a numeric value into a varchar SQL? ›The CAST() function converts a value (of any type) into a specified datatype.
How do you assign a value from a select statement to a variable in SQL? ›To assign a value to a variable, use the SET statement. This is the preferred method of assigning a value to a variable. A variable can also have a value assigned by being referenced in the select list of a SELECT statement.
How do I convert int to numeric in SQL? ›
Use the CAST() function to convert an integer to a DECIMAL data type. This function takes an expression or a column name as the argument, followed by the keyword AS and the new data type. In our example, we converted an integer (12) to a decimal value (12.00).
What is the difference between CAST and convert in SQL? ›1. CAST and CONVERT are two SQL functions used by programmers to convert one data type to another. 2. The CAST function is ANSI standard and is compatible to use in other databases while the CONVERT function is a specific function of the SQL server.
What is difference between int and varchar in SQL? ›Integer is for numbers, and varchar is for numbers, letters and other characters (Short text). So for age you can use a int type, for genders you can use the enum() type if there are only two options. Varchar is text and integer is number.
How do you concatenate int and varchar columns in SQL? ›In your case, you will need to convert your int to varchar like Convert(varchar(10),STUD_ID) firstly; then select all the STUD_ID in new varchar type with the same STUD_Dept combine together with commar before each of them; at last use stuff() to replace the first commar.
How to convert datatype of a column in SQL? ›- SQL Server / MS Access: ALTER TABLE table_name. ALTER COLUMN column_name datatype;
- My SQL / Oracle (prior version 10G): ALTER TABLE table_name. MODIFY COLUMN column_name datatype;
- Oracle 10G and later: ALTER TABLE table_name.
Answer: The error is due to an invalid date format being saved to the custom_rmh_rooms_history SQL table. To resolve this issue, the Windows Regional settings need to be modified and the Short Date format needs to be in MM/dd/yyyy format.
Which syntax is correct in converting string data type to integer? ›Use Integer.parseInt() to Convert a String to an Integer
This method returns the string as a primitive type int.
The most obvious way to fix this is to change the string to resemble an actual date. Or if it does resemble a date, change the string literal to a format that can be converted to the particular date/time type that we're trying to convert it to.
What happens when you cast a char to an int? ›If we direct assign char variable to int, it will return the ASCII value of a given character. If the char variable contains an int value, we can get the int value by calling Character.getNumericValue(char) method.
How would you cast convert a string variable to an integer? ›To convert, or cast, a string to an integer in Python, you use the int() built-in function. The function takes in as a parameter the initial string you want to convert, and returns the integer equivalent of the value you passed. The general syntax looks something like this: int("str") .
Can we just cast the reference to an int? ›
Yes, you can cast the reference(object) of one (class) type to other.
Should I use varchar or int? ›1 Answer. Int comparisons are faster than varchar comparisons, and ints take much less space than varchars. This is applicable true for both unindexed and indexed access. You can use an indexed int column to make it faster.
Can varchar have a default value? ›A DEFAULT value clause in a data type specification explicitly indicates a default value for a column. Examples: CREATE TABLE t1 ( i INT DEFAULT -1, c VARCHAR(10) DEFAULT '', price DOUBLE(16,2) DEFAULT 0.00 ); SERIAL DEFAULT VALUE is a special case.
Is varchar a string or int? ›Values in VARCHAR columns are variable-length strings. The length can be specified as a value from 0 to 65,535. The effective maximum length of a VARCHAR is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used.
What is the difference between CHAR () and VARCHAR ()? ›The fundamental difference between CHAR and VARCHAR is that the CHAR data type is fixed in length, while the VARCHAR data type supports variable-length columns of data. But they are also similar. They both can store alphanumeric data.
When should I use CHAR instead of VARCHAR? ›Use char when the sizes of the column data entries are consistent. Use varchar when the sizes of the column data entries vary considerably. Use varchar(max) when the sizes of the column data entries vary considerably, and the string length might exceed 8,000 bytes.
Do you need to specify VARCHAR? ›Always specify a length to any text-based datatype such as NVARCHAR or VARCHAR . Don't over-use the MAX specification either as the resulting column then can't be indexed and comes with performance baggage.
What is CAST () and convert () functions in SQL Server? ›The SQL CAST function is mainly used to convert the expression from one data type to another data type. If the SQL Server CAST function is unable to convert a declaration to the desired data type, this function returns an error. We use the CAST function to convert numeric data into character or string data.
How to convert decimal value to integer in SQL Server? ›Using ROUND() function: This function in SQL Server is used to round off a specified number to a specified decimal places. Using FLOOR() function: It returns the largest integer value that is less than or equal to a number.
How do I convert a string to a numeric value? ›You convert a string to a number by calling the Parse or TryParse method found on numeric types ( int , long , double , and so on), or by using methods in the System.Convert class.
How do I assign a static value to a SELECT query? ›
Selecting Static Values
Static values can be inserted into a resultset returned from a SELECT query as another column. Simply use the static value as a column to select, and the query will return a column where the name of the column is the static value, and every row in that column will return that same static value.
You can pass parameters/arguments to your SQL statements by programmatically creating the SQL string using Scala/Python and pass it to sqlContext. sql(string). Note the 's' in front of the first """. This lets you substitute $param's in a Scala string.
Which operator do we use in SQL SELECT statement to compare a value to a set of specified values? ›The IN operator is used to compare a value to a list of literal values that have been specified. The LIKE operator is used to compare a value to similar values using wildcard operators.
What is the difference between CAST and convert? ›CAST is part of the ANSI-SQL specification; whereas, CONVERT is not. In fact, CONVERT is SQL implementation-specific. CONVERT differences lie in that it accepts an optional style parameter that is used for formatting.
How to convert int to string in SQL Server query? ›Using GUI. Then we can use the GUI to change the data type of the table from an int into a string. In SSMS, we can use the Design option to change the data type, by right clicking on the table name. In the designer, change the data type of OrderQty from an int into nvarchar(50) and save the changes.
How do I format a numeric field in SQL? ›SQL Format Number Options
Using CAST - SELECT CAST(5634.6334 as int) as number. Using CONVERT - SELECT CONVERT( int, 5634.6334) as number. Using ROUND - SELECT ROUND(5634.6334,2) as number. Using CEILING - SELECT FLOOR(5634.6334) as number.
Finally, let's look at how to declare an INT variable in SQL Server and assign an inital value. For example: DECLARE @site_value INT = 10; This variable declaration example would declare a variable called @site_value that is an INT datatype.
How do you change the datatype of a column in my SQL? ›- SQL Server / MS Access: ALTER TABLE table_name. ALTER COLUMN column_name datatype;
- My SQL / Oracle (prior version 10G): ALTER TABLE table_name. MODIFY COLUMN column_name datatype;
- Oracle 10G and later: ALTER TABLE table_name.
To convert a String to INT uses sql conversion functions like cast or convert.
Can varchar be integer? ›VARCHAR (length)
A VARCHAR declaration must include a positive integer in parentheses to define the maximum allowable character string length. For example, VARCHAR(n) can accept any length of character string up to n characters in length. The length parameter may take any value from 1 to the current table page size.
How to convert string to integer in SQL? ›
- TO_NUMBER(stringExpression) converts the input string expression to a canonical number of data type NUMERIC. If the string expression is of data type DOUBLE, TO_NUMBER returns a number of data type DOUBLE. ...
- TONUMBER(stringExpression) is equivalent to TO_NUMBER(stringExpression).
CONVERT is SQL Server specific, CAST is ANSI. CONVERT is more flexible in that you can format dates etc. Other than that, they are pretty much the same. If you don't care about the extended features, use CAST .
How to assign value to variable in select statement in SQL Server? ›To assign a value to a variable, use the SET statement. This is the preferred method of assigning a value to a variable. A variable can also have a value assigned by being referenced in the select list of a SELECT statement.