I'm using the SQLite C interface to write an application. Since I like security, I'm using prepared statements to query the database. In one such query, I'm selecting rows from a virtual database using the MATCH keyword for full-text-searching. Here's an example:
SELECT * FROM Emails
WHERE ( Subject LIKE ?001 OR ?001 IS NULL )
AND ( Author LIKE ?002 OR ?002 IS NULL )
AND ( Body MATCH ?003 OR ?003 IS NULL )
This allows the user to enter any terms (Subject, Author, or Body) individually or in any combination to do a search. Any term that isn't entered, I'll bind NULL to that parameter. The problem with that statement is that you can't use the OR keyword with the MATCH keyword. I'm looking for a statement I can use with the MATCH keyword to return all rows if not searching in the Body column. Is there such a statement?
I suggest the following:
SELECT * FROM emails
WHERE ...
AND ( CASE (SELECT COUNT(*) FROM emails WHERE body MATCH ?003)
WHEN 0 THEN 1
ELSE body MATCH ?003
END )
I ended up modifying the SQL statement at runtime to replace MATCH with LIKE '%'. Not very elegant, but it works for now.
Related
I was trying to order a result set by the order of the values in an IN() clause.
SELECT * FROM CrossReference WHERE cross_reference_id IN (SELECT Id FROM FilteredIds)
So I tried to find a function such as MySql FIELD(). Then I found these answers (answer1, answer2) which explain how to do the exact thing on SQLite using the INSTR().
SELECT *, INSTR(',GDBR10,GDBR5,GDBR30,', ',' || ticker || ',') POS
FROM tbl
WHERE POS>0
ORDER BY POS;
So it's working as expected, but I want to populate the ids dynamically using a select query. I tried many approaches, but nothing seemed to work. Here is the last one I tried. It gave me just one result row (a result related to the first filterId).
SELECT *, INSTR (','||(SELECT id FROM FilteredIds)||',', ',' || cross_reference_id || ',') POS FROM CrossReference WHERE POS>0 ORDER BY POS;
So I guess I'm making some kind of mistake when concatenating the SELECT query with the rest of the code. Because when I manually enter the filtered Ids it works and returns results according to the entered filter ids.
I'm trying to create a trigger in which, only under certain circumstances, an insert is performed on another table. Consider the following code:
create table journal (
pk integer primary key autoincrement,
dsc varchar(10) not null
);
create table users (
name varchar(30) primary key not null
);
create trigger users_ai
after insert on users
begin
select
case
when 1 then
insert into journal(dsc) values('foo')
end;
end;
I get the following error when I run this code:
Error: near line 10: near "insert": syntax error
In production, the "1" in the when clause would be replaced by a more complex expression. I've also tried "true" and get the same results. I've also tried surrounding the insert statement in parens and get the same results. Any ideas how to accomplish what I want?
If you look at the syntax diagram for "CREATE TRIGGER", you'll see your attempt just doesn't match. You can, however, simply use the WHEN branch (without needing FOR EACH ROW):
create trigger users_ai
after insert on users
when 1 begin
insert into journal(dsc) values('foo');
end;
OK, figured it out. Instead of putting a conditional expression in the block of the trigger, I used a when clause. Here's the code that works:
create trigger users_ai
after insert on users when 1
begin
insert into journal(dsc) values('foo');
end;
If that when expression is changed to something that returns false (say 0) then the insert isn't done. In production, the expression will sometimes return true, sometimes false, which, of course, is the point of this code. Thanks everybody!
I think that you want a CASE statement, not a CASE expression.
create trigger users_ai after insert on users
begin
case
when ... then insert into journal(dsc) values('foo');
when ... then ...;
else ...;
end case;
end;
Note: if your trigger needs access to the data that was just inserted, its definition should the for each row option.
You can try to use an INSERT ... SELECT and your expression in the WHERE clause.
...
INSERT INTO journal
(dsc)
SELECT 'foo'
WHERE 1 = 1;
...
1 = 1 needs to be replaced by your Boolean expression.
I am trying to assign or give all permissions of a user to another given user, 13053 but facing this Oracle error, ORA-01427: single-row subquery returns more than one row and i know exactly which part of my SQL statement shown below is returning this error but failed to handle it because what i want to achieve is to give those multiple rows returned to the given user with an id of 13053.
My attempt
INSERT INTO userpermissions (
userid,permissionid
) VALUES (
13053,( SELECT permissionid
FROM userpermissions
WHERE userid = ( SELECT userid
FROM users
WHERE username = '200376'
)
)
);
Any help ?
Thanks in advance.
A rewrite ought to do the trick:
INSERT INTO USERPERMISSIONS(
USERID,
PERMISSIONID
)
SELECT 13053 AS USERID,
p.PERMISSIONID
FROM USERPERMISSIONS p
WHERE p.userid = (SELECT userid FROM users WHERE username = '200376');
The problem with the original insert is that you are using single-row insert syntax when you are really trying to insert a set of rows.
Including the target userid as a literal is one way to make the set of rows look the way I am assuming you intend.
I am having trouble getting a block of pl/sql code to work. In the top of my procedure I get some data from my oracle apex application on what checkboxes are checked. Because the report that contains the checkboxes is generated dynamically I have to loop through the
APEX_APPLICATION.G_F01
list and generate a comma separated string which looks like this
v_list VARCHAR2(255) := (1,3,5,9,10);
I want to then query on that list later and place the v_list on an IN clause like so
SELECT * FROM users
WHERE user_id IN (v_list);
This of course throws an error. My question is what can I convert the v_list to in order to be able to insert it into a IN clause in a query within a pl/sql procedure?
If users is small and user_id doesn't contain commas, you could use:
SELECT * FROM users WHERE ',' || v_list || ',' LIKE '%,'||user_id||',%'
This query is not optimal though because it can't use indexes on user_id.
I advise you to use a pipelined function that returns a table of NUMBER that you can query directly. For example:
CREATE TYPE tab_number IS TABLE OF NUMBER;
/
CREATE OR REPLACE FUNCTION string_to_table_num(p VARCHAR2)
RETURN tab_number
PIPELINED IS
BEGIN
FOR cc IN (SELECT rtrim(regexp_substr(str, '[^,]*,', 1, level), ',') res
FROM (SELECT p || ',' str FROM dual)
CONNECT BY level <= length(str)
- length(replace(str, ',', ''))) LOOP
PIPE ROW(cc.res);
END LOOP;
END;
/
You would then be able to build queries such as:
SELECT *
FROM users
WHERE user_id IN (SELECT *
FROM TABLE(string_to_table_num('1,2,3,4,5'));
You can use XMLTABLE as follows
SELECT * FROM users
WHERE user_id IN (SELECT to_number(column_value) FROM XMLTABLE(v_list));
I have tried to find a solution for that too but never succeeded. You can build the query as a string and then run EXECUTE IMMEDIATE, see http://docs.oracle.com/cd/B19306_01/appdev.102/b14261/dynamic.htm#i14500.
That said, it just occurred to me that the argument of an IN clause can be a sub-select:
SELECT * FROM users
WHERE user_id IN (SELECT something FROM somewhere)
so, is it possible to expose the checkbox values as a stored function? Then you might be able to do something like
SELECT * FROM users
WHERE user_id IN (SELECT my_package.checkbox_func FROM dual)
Personally, i like this approach:
with t as (select 'a,b,c,d,e' str from dual)
--
select val
from t, xmltable('/root/e/text()'
passing xmltype('<root><e>' || replace(t.str,',','</e><e>')|| '</e></root>')
columns val varchar2(10) path '/'
)
Which can be found among other examples in Thread: Split Comma Delimited String Oracle
If you feel like swamping in even more options, visit the OTN plsql forums.
Given the following tables:
create table index(name text, docid int);
create virtual table docs using fts4();
The following query works as intended when querying for a single token (for example: march, or bad):
select name from index where docid in (select docid from docs where docs match ?)
But how can I query for more than one token (say, bad bed)? Binding the string bad bed directly does not work (always selects nothing), neither surrounding the placeholder or the string with double quotes, nor using AND to MATCH each token separetly (this last one throws an error).
Using intersect does work, but it's clunky and innefficient when searching for many tokens:
select name from index where docid in (
select docid from docs where docs match ?
intersect
select docid from docs where docs match ?
intersect
...
)
Each ? is paired with a single token.
You can use the concatenation operator || in sqlite. '' would be the empty string
SELECT * FROM table WHERE docs MATCH '' || ? || ' ' || ? || ' ' || ? || ''
Make sure there is a space between every token or an ' AND '.
Update
Actually it doesn't work. It seems there are tokenator issues with this approach. Its better to concatenate all the tokens with the space and bind the resulting string with a single '?'
There are operators within the match syntax in FTS so you can use AND, OR and NOT.
See here for documentation
e.g.
-- Return the docid values associated with all documents that contain the
-- two terms "sqlite" and "database", and/or contain the term "library".
SELECT docid FROM docs WHERE docs MATCH 'sqlite AND database OR library';