I am having a hell of a time trying to add two calculated fields in a query together. My first record has field1= 1, and field2= 5, and the field that is trying to add them as 15!
So it’s treating them as a string.
When I try to use the function of SUM() I get an error of some of the other fields not being used in expressions, which I don’t understand.
Subtracting the two fields works as does multiplication.
I am unable to change the format of either fields in the properties as the drop down menu is blank.
Please help!
Aggregate functions act on rows not fields. Sum(field1) adds the values of field1 for group of records. Use aggregate functions in an aggregate (GROUP BY) query.
Plus (+) character will concatenate text values but add numeric. Apparently, your two fields are providing text values. Either correct the field data type or use function to convert values to number. Convert at least one field and Access will perform arithmetic instead of concatenation on all terms of expression.
Val(field1) + field2
This assumes no fields are Null. Number conversion functions will error with Null. Also, arithmetic with Null returns Null. If Null is possibility, handle with Nz().
Val(Nz(field1,0)) + Nz(field2,0)
Related
I have created an SSIS package where two columns of type varchar(1) have to be mapped to columns of Integer. I have this working using a Derived Column and giving both fields a type cast of (DT_I4). However, I discovered in the complete data set there are records with no value in these two fields and so I have to Type Cast AND add a condition in expression to default to "0" if null.
So far I have tried the following but are not valid
(IsNull[Notes Taken])?(DT_I4)"0":[Notes Taken]
(DT_I4)(IsNull[Notes Taken])?"0":[Notes Taken]
How do I create this expression properly
The most simple solution is to use REPLACENULL function like:
REPLACENULL([Notes Taken], "0")
And then - cast it to DT_I4. This function replaces the logic you are devising with conditional operator.
Your both formulas have errors. The most prominent - ISNULL is a function and needs parenthesis around its arguments, ISNULL([Notes Taken]), brackets only define a dataflow column. See MS Docs.
Then, your first expression
(IsNull[Notes Taken])?(DT_I4)"0":[Notes Taken]
Possibly the field [Notes Taken] is not matching data type of the DT_I4 which is the datatype of the first argument of ? : operator.
Your second expression
(DT_I4)(IsNull[Notes Taken])?"0":[Notes Taken]
Applies the data cast to the logical function ISNULL, not to the complete expression. You should put the parenthesis around the complete ? : operator like:
(DT_I4)(IsNull([Notes Taken])?"0":[Notes Taken])
I have a table on my MySQL db named membertable. The table consists of two fields which are memberid and membername. The memberid field has the type of integer and uses auto_increment function starting from 2001. The membername table has the type of varchar.
The membertable has two records with the same order as described above. The records look like this :
memberid : 2001
membername : john smith
memberid : 2002
membername : will smith
I found something weird when I ran a SELECT statement against the memberid field. Running the following statement :
SELECT * FROM `membertable` WHERE `memberid` = '2001somecharacter'
It returned the first data.
Why did that happen? There's no record with memberid = 2001somecharacter. It looks like MySQL only search the first 4 character (2001) and when It's found related data, which is the returned data above, it denies the remaining characters.
How could this happen? And is there any way to turn off this behavior?
--
membertable uses innodb engine
This happens because mysql tries to convert "2001somecharacter" into a number which returns 2001.
Since you're comparing a number to a string, you should use
SELECT * FROM `membertable` WHERE CONVERT(`memberid`,CHAR) = '2001somecharacter';
to avoid this behavior.
OR to do it properly, is NOT put your search variable in quotes so that it has to be a number otherwise it'll blow up because of syntax error and then in front end making sure it's a number before passing in the query.
sqlfiddle
Your finding is an expexted MySQL behaviour.
MySQL converts a varchar to an integer starting from the beginning. As long as there are numeric characters wich can easily be converted, they are icluded in the conversion process. If there's a letter, the conversion stops returning the integer value of the numeric string read so far...
Here's some description of this behavior on the MySQL documentation Site. Unfortunately, it's not mentioned directly in the text, but there's an example which exactly shows this behaviour.
MySQL is very liberal in converting string values to numeric values when evaluated in numeric context.
As a demonstration, adding 0 causes the string to evaluated in a numeric context:
SELECT '2001foo' + 0 --> 2001
, '01.2-3E' + 0 --> 1.2
, 'abc567g' + 0 --> 0
When a string is evaluated in a numeric context, MySQL reads the string character by character, until it encounters a character where the string can no longer be interpreted as a numeric value, or until it reaches the end of the string.
I don't know of a way to "turn off" or disable this behavior. (There may be a setting of sql_mode that changes this behavior, but likely that change will impact other SQL statements that are working, which may stop working if that change is made.
Typically, this kind of check of the arguments is done in the application.
But if you need to do this in the SELECT statement, one option would be cast/convert the column as a character string, and then do the comparison.
But that can have some significant performance consequences. If we do a cast or convert (or any function) on a column that's in a condition in the WHERE clause, MySQL will not be able to use a range scan operation on a suitable index. We're forcing MySQL to perform the cast/convert operation on every row in the table, and compare the result to the literal.
So, that's not the best pattern.
If I needed to perform a check like that within the SQL statement, I would do something like this:
WHERE t.memberid = '2001foo' + 0
AND CAST('2001foo' + 0 AS CHAR) = '2001foo'
The first line is doing the same thing as the current query. And that can take advantage of a suitable index.
The second condition is converting the same value to a numeric, then casting that back to character, and then comparing the result to the original. With the values shown here, it will evaluate to FALSE, and the query will not return any rows.
This will also not return a row if the string value has a leading space, ' 2001'. The second condition is going to evaluate as FALSE.
When comparing an INT to a 'string', the string is converted to a number.
Converting a string to a number takes as many of the leading characters as it can and still be a number. So '2001character' is treated as the number 2001.
If you want non-numeric characters in member_id, make it VARCHAR.
If you want only numeric ids, then reject '200.1character'
Hi I have been trying to select the records whose column has no integer I have this piece of code and tried it different ways but still get back rows with P992142
P992142
P301716
P301716
P307162
P306522
which I don't want
select practitioner_id
from claimsprofinload
WHERE practitioner_id not like '%[0-9]%';
You're using a regular expression in conjunction with LIKE, which is not valid. What you want is the REGEXP or RLIKE comparison.
Since that expression is evaluated as a more literal string, and since none of your rows have [0-9] literally in them, it matches all rows.
I have a table that contain a field names as mgrs, the value that stored in mgrs fields is like '42SWC227821555' may contain more charachters, and may contain lower case letters. So now i want to search records between two mgrs, so how can i do that? can i convert mgrs value to integer first and then use in between clause?
Instead of BETWEEN clause use STRCMP(expr1, expr2) function for string comparison operations:
WHERE STRCMP(mgrs, '42SWC227821555') >= 0 AND STRCMP(mgrs, '42SWC227821570') <= 0
You can use string expressions with BETWEEN comparison.
SELECT '42SWC2278215551' BETWEEN '42SWC227821555' AND '42SWd227821555'
-> 1
I will list some steps, instead of complete answer.
Remove all alphabets from you value, means you can have 1 more customized column using function listed on this link
Apply your filter on this column.
I have a table with a field value which is a varchar(255). The contents of the field can be quite varied:
$1.20
$2994
$56 + tax (This one can be ignored or truncated to $56 if necessary)
I have a query constructed:
SELECT value FROM unnamed_table ORDER BY value
However, this of course uses ASCII string comparison to order the results and does not use any numerical type of comparison.
Is there a way to truly order by value without changing the field type to DECIMAL or something else? In other words, can the value field be modified ('$' removed, value converted to decimal) on the fly before the results are sorted?
You could sort on an expression made to "parse" the text into decimal
SELECT value FROM unnamed_table ORDER BY expression_returning_decimal(value)
Where your expression uses MySQL functions to extract the number from the string depending on what form you expect it to take (something like CAST(value AS DECIMAL(10,2)), but you'll probably need to deal with the extraneous non-numeric characters somehow as I'm not sure what the CAST will give if you don't strip them).
Create a second column without the $-sign, sort on that one and use the data of the original column in your application.
In order to create the helper column and sort on it you would need something like this:
SELECT value, CAST(SUBSTR(value, 2) AS UNSIGNED) sort_col
FROM unnamed_table ORDER BY sort_col