Iphone: How to read return value of strftime SQLite function
I need to read the column value of the following query
SELECT strtime('%Y-%m', created_at) as field FROM table GROUP BY field
the type of column field is 3 (I assum开发者_Python百科e it is blog), but I need string
How should I?
Updated
const char* sql = "SELECT CAST(strftime('%Y', created_at) as INTEGER) as year FROM table GROUP BY year
if (SQLITE_OK == sqlite3_prepare_v2([AppDelegate db], sql, -1, &queryhandle, NULL)){ while(SQLITE_ROW == sqlite3_step(queryhandle)){
NSSTring* year = [NSString stringWithFormat:@"%d",sqlite3_column_int(queryhandle, 0)];
this code gives me 3460 as year
(have checked cast as integer, and cast as varchar and sqlite3_column_text function)
As long as created_at
has a time string format as specified in the sqlite docs, it doesn't matter what storage type is used in a particular tuple (although you can find out using the typeof
) function. The result of the strftime
function (you aliased it as field
) is either text or null.
CREATE TABLE t (x BLOB);
INSERT INTO t VALUES ("2010-03-29\x0"), ("2010-03-28");
SELECT strftime("%Y-%m", x), typeof(strftime("%Y-%m", x)), typeof(x) FROM t;
|null|text
2010-03|text|text
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