Is there any function like IFERROR in MySQL. For example:
IFERROR(25/0,9)
I tried on phpmyadmin but it said that such function IFERROR does not exist. Really appreciate any help
YOu can reach similar results with IFNULL:
If an answer is not valid, it defaults to NULL. The IFNULL will then give you the alternative answer:
Your example (in this case):
SELECT IFNULL(25/0,9);
Gives as result: 9
Related
I have a calculated field on a table at MS Access and I'd like to use the following syntax, but it returns a syntax error pop-up and and I'm wondering which part is wrong. Could you please help with this? Thanks a lot.
IIf([Letter_Grade]="A+",4,IIf([Letter_Grade]="A",4,IIf([Letter_Grade]="A",3.7,IIf([Letter_Grade]="B+",3.3,IIf([Letter_Grade]="B",3,IIf([Letter_Grade]="B",2.7,IIf([Letter_Grade]="C+",2.3,IIf([Letter_Grade]="C",2,IIf([Letter_Grade]="C",1.7,IIf([Letter_Grade]="D+",1.3,IIf([Letter_Grade]="D",1,IIf([Letter_Grade]="D-",0.7,IIf([Letter_Grade]="F",0)))))))))))))
Try adding ",null" after your last expression:
IIf([Letter_Grade]="F",0,null)))))))))))))
Though it may be better to use a query?
The function works well, did you put = operator before it.
Attached are some images of the results I got and the function
I have a curious question that's going on my mind while looking at my datatables.
I noticed that some columns of my table has no values, like just the column only.
Is it possible when you want to call that column it will return a value of 0?
I tried to call it with a simple SELECT query in sql but its giving me a notice.
Notice: Trying to get property of non-object MySQL result on line (number line)
Can this be used with an if-else statement from the query or a case statement from the query? Hoping for your opinions on this. Thank you :)
Try to use some function like NVL() in Oracle, or IFNULL() in MySQL. This functions set a value when you got a NULL value.
In the query below, I would like to make the "Percent" value 0 when it is NULL. However, I can't seem to figure out how to wrap the IFNULL function into my query properly. Any help would be appreciated!
SELECT number, ((DATEDIFF (scheduled_start_date,gate_3_start_date) - DATEDIFF (scheduled_due_date,gate_4_delivery_date))*100 / (DATEDIFF (scheduled_due_date,gate_4_delivery_date))) as 'Percent' FROM dashboard
Use MySql's coalesce
http://dev.mysql.com/doc/refman/5.0/en/comparison-operators.html#function_coalesce
it should work for you. I can provide an example if you need it.
Background
Creating a wrapper function for a SQL statement.
Problem
A function returns 1 row, whereas the query upon which the function is based returns 100+ rows. The parameter values are identical:
SELECT * FROM as_rpt.tasc_fsa( 'ABC', '2010-01-01'::date, '2011-01-01'::date );
The tasc_fsa function is a SELECT statement with a few table joins; the function language is 'sql' rather than 'plpgsql'.
Question
What reasons would a function return a single row yet the exact same query that the function uses, when not called via the function, correctly returns over 100 rows?
Any ideas would be most helpful.
Thank you!
Have you use RETURN SETOF ...?
SETOF indicates you want to return more than 1 row.
I'm pretty sure you forgot to use 'RETURN SETOF'.
You mention the function "joins a few tables". Your example obviously doesn't. If there are joins being performed, it is possible this is causing less results.
The way the dates are being interpreted is another possibility. When you get 1 answer, is it within the range you specify?
I'm trying to do some queries but I keep getting errors, now I'm thinking that there is something wrong with the mysql installation. Can anybody tell me if there is an error in this query?
SELECT settings.ID,
settings.name,
settings.description,
NVL2(userSettings.value, userSettings.value, settings.default)
FROM settings
LEFT OUTER JOIN userSettings ON (settings.ID = userSettings.settingID)
The error I get says the function databaseX.NVL2 does not exist
I recommend staying away from vendor specific functions when a ANSI standard equivalent alternative is available. NVL and IFNULL for example can (often) be replaced with COALESCE.
You can also use CASE WHEN, which means a lot more typing on the downside, but the upside is that people with background in SQL Server for example won't have to deal with Oracles DECODE() or NVL or NVL2, because the logic is right there in the code.
That's probably because NVL2 is an Oracle function, not a MySQL function. I believe the function you are looking for in MySQL would be COALESCE()
As #Eric Petroelje mentioned NVL2() is Oracle function, not MySQL. However MySQL has its own equivalent that can be used in this case: IFNULL():
SELECT ... IFNULL(userSettings.value, settings.default) ...
After several try&error probes, I found this method to emulate Oracle's NVL2 function. It's not very elegant, but it works
SELECT IF(LENGTH(ISNULL(FieldName, '')) > 0, 'Not NULL Value', 'Null Value') FROM TableName
I think this can help you
IF(expr1,expr2,expr3)
If expr1 is TRUE (expr1 <> 0 and expr1 <> NULL) then IF() returns expr2; otherwise it returns expr3. IF() returns a numeric or string value, depending on the context in which it is used.
Alternatively you can substitute NVL2 to:
IF (userSettings.value IS NULL, userSettings.value, settings.default)