SQlite3: Select statement...WHERE clause

[ManWithMask]

I am trying to get a row and return a column from the fetched row, but somehow it is not working. I suspect my syntax is wrong.

I have declared an int variable ("Key") and populate its value from another table and want to use this to select the row.

NSInteger Key = [mydetailsTable.AgeNB integerValue];

My NSLog reports the correct value from the other table:

2010-05-20 17:56:03.941 Ifa[13992:207] Key: 48

If I hard code the value, then it gets the row and returns the correct Rate.

const char *sql = "SELECT Rate from PremiumRates WHERE AgeNB = 48"//works;

const char *sql = "SELECT Rate from PremiumRates WHERE AgeNB = Key";//does not work

If I use the int variable it does not find the row.

I have looked around, but there seem very few examples of the format of the WHERE clause when trying to return selected rows.

Anyone who can help me? Much appreciated!!!!

[reubensammut]

Originally Posted by ManWithMask

I am trying to get a row and return a column from the fetched row, but somehow it is not working. I suspect my syntax is wrong.

I have declared an int variable ("Key") and populate its value from another table and want to use this to select the row.

NSInteger Key = [mydetailsTable.AgeNB integerValue];

My NSLog reports the correct value from the other table:

2010-05-20 17:56:03.941 Ifa[13992:207] Key: 48

If I hard code the value, then it gets the row and returns the correct Rate.

const char *sql = "SELECT Rate from PremiumRates WHERE AgeNB = 48"//works;

const char *sql = "SELECT Rate from PremiumRates WHERE AgeNB = Key";//does not work

If I use the int variable it does not find the row.

I have looked around, but there seem very few examples of the format of the WHERE clause when trying to return selected rows.

Anyone who can help me? Much appreciated!!!!

try this

NSString *s = [NSString stringWithFormat:@"SELECT SELECT Rate from PremiumRates WHERE AgeNB = %d", Key];
	
const char *sql = [s cStringUsingEncoding:NSASCIIStringEncoding];

[ManWithMask]

That worked and the correct Rate is being returned. Now I understand how to set up the WHERE clause for selected records. Hope this will help others as well.

Thanks a million.

[ManWithMask]

Hi Reuben,

Is there any documentation on the % parameters one can use in such a select method. If my Key is a string var, then the %d will not work. I have trawled around looking for some useful documentation and cannot find someone who has put together anything useful on the parameter options following the %. Seems like most people want to SELECT all the records and very few include a WHERE clause in their SELECT.

Thanks in advance!

Originally Posted by reubensammut

try this

NSString *s = [NSString stringWithFormat:@"SELECT SELECT Rate from PremiumRates WHERE AgeNB = %d", Key];
	
const char *sql = [s cStringUsingEncoding:NSASCIIStringEncoding];

[Tambourin]

if key is an NSString use %@

check your C language book for documentation about %

[reubensammut]

Yes I suggest you read this as there are some Objective-C specific Format Specifiers like %@ for objects like NSString