On Fri, 23 Dec 2011 04:40:53 +0000, YAN HONG YE <[email protected]>
wrote:
>I have a question about C binding for sqlite, I have a table like this:
>
>Name Price1 Price2 Sum
>A1 23 231
>A2 22 12
>A3 21 223
>
>how to use functin
> int myfunc()
>{
>int tt=0;
>if (price1 >2)
>tt++;
>if (price2>1)
>tt++;
>if (price2>12)
>tt++;
>
>...
>return tt
>
>}
>
> to put function result into my table last added
> column use sqlite in c code?
To use SQLite from C, you have to use the C API.
http://www.sqlite.org/c3ref/funclist.html
Here are a few examples:
http://www.sqlite.org/cvstrac/wiki?p=SimpleCode
http://icculus.org/~chunky/stuff/sqlite3_example/sqlite3_example_bind.c
Assuming tt is what you would want to see in the sum column, there is no
need to use C:
CREATE TABLE t1 (
Name TEXT,
Price1 INTEGER,
Price2 INTEGER
);
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A1',23,231); -- 3
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A2',22,12); -- 2
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A3',21,223); -- 3
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A4',1,1); -- 0
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A5',1,2); -- 1
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A6',1,13); -- 2
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A7',3,1); -- 1
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A8',3,2); -- 2
INSERT INTO t1 (Name,Price1,Price2) VALUES ('A9',3,13); -- 3
CREATE VIEW t1_with_sum AS
SELECT Name,
Price1,
Price2,
(Price1 > 2) + (Price2 > 1) + (Price2 > 12) AS Sum
FROM t1
ORDER BY Name;
.headers on
SELECT * FROM t1_with_sum;
outputs:
Name|Price1|Price2|Sum
A1|23|231|3
A2|22|12|2
A3|21|223|3
A4|1|1|0
A5|1|2|1
A6|1|13|2
A7|3|1|1
A8|3|2|2
A9|3|13|3
Note: the sum column should not be part of the table, as it is a derived
value. If you really want to add that column, you can populate it with:
UPDATE t1 set Sum=(Price1 > 2) + (Price2 > 1) + (Price2 > 12);
SELECT * FROM t1 ORDER BY Name;
(same output)
Hope this helps.
--
Regards,
Kees Nuyt
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