Scenario is like this:
list of different types of insurance [ID, name, desc]
each insurance has a different unique table. [ID, user_id, ]
I want to query to show the columns of Insurance like [ID, Name, DESC] and a new column to show whether this user has applied for this insurance or not. No need to worry for the user part.
Just guide me how can I sub-query with dynamic table name.
I tried making a setup table where each insurance maps to its table name. But in my sub query how to do that.
If user has applied then show 1 otherwise 0.
SELECT i1.ID,
i1.name,
i1.desc,
IF(true, 1, 0) AS EXIST
#(SELECT t1.c_user_id FROM #tbl_name t1 WHERE t1.id = '101')
FROM app_fd_pdrm_insur_type i1;
Please, guide me what to replace with true.
Thank you.
Try this:
SELECT i1.ID, i1.name, i1.desc, IF( EXISTS(SELECT t1.c_user_id FROM #tbl_name t1 WHERE t1.id = '101'), 1, 0) as Exists FROM app_fd_pdrm_insur_type i1;
Related
I have 2 queries:
SELECT COUNT(*) FROM a WHERE id = 1
//if row == 1
INSERT INTO a VALUES(fielda) VALUES('value')
Is there a way to merge these two queries into one? I tried with 'IF (count> 0, ..)' and similar, but the query is incorrect.
This involves inserting a new record into the table, taking care not to exceed a pre-set number of records for each field.
In theory it should be similar to an INSERT IF ...
Edit:
#Barmar I tried but I think I did not understand what you wrote (in fact I made a mistake in the query), I try to answer like this:
THE QUERY AFTER YOUR RESPONSE:
INSERT INTO table1 SELECT MAX(id) FROM table1 WHERE field1 = (SELECT id from a WHERE f = field2) HAVING COUNT(*) = 1 (all fields request) VALUES (all values request)
//field1 = id from table2
//field2 = id from another table: associative value
//ORIGINAL QUERY
//FIRST COUNT:
SELECT COUNT(*) from table1 WHERE field1 = (SELECT id FROM table2 WHERE f = field2)
//AFTER THE INSERT:
INSERT INTO table1 (all fields request) VALUES (all values request)
I came to mind this example I try to show you:
TABLE PLAYER: fields(ID, TEAMID, NAME) => (id=int, teamid=int associate to table team, name=varchar)
TABLE TEAM: fields(ID NAME) => (id=int, name=varchar)
Suppose that the players in a team are maximum 20, so you expect maximum 20 records associated by the player table for the same teamid value, or at least this is what we humans think, because for the computer can also be infinite. I was looking for a way to allow the insertion only in the case in which it is actually permissible to insert records, in this case the condition is that in the players table there are less than 21 records per team.
You can use INSERT ... SELECT, and put the condition in the SELECT query.
INSERT INTO player (teamid, name)
SELECT #teamid, #playername
FROM DUAL
WHERE (SELECT COUNT(*) FROM player
WHERE teamid = #teamid) < 20
DUAL is a dummy table when you need to select literal data, but need to include other clauses in the query.
Hi I am making a webrowser game and I am trying to get monsters into my data base when I get the error:
Subquery returns more then 1 row
here is my code
INSERT INTO monster_stats(monster_id,stat_id,value)
VALUES
( (SELECT id FROM monsters WHERE name = 'Necroborg!'),
(SELECT id FROM stats WHERE short_name = 'atk'),
2);
any ideas how to fix this problem?
Try use LIMIT 1
INSERT INTO monster_stats(monster_id,stat_id,value) VALUES ((SELECT id FROM monsters WHERE name = 'Necroborg!' LIMIT 1),(SELECT id FROM stats WHERE short_name = 'atk' LIMIT 1),2);
Or you could use Insert from select, with join, if you have relations with 2 tables.
INSERT INTO monster_stats(monster_id,stat_id,value)
(SELECT monsters.id, stats.id, 2 as value FROM monsters
LEFT JOIN stats on monsters.id = stats.monsters_id
WHERE monsters.name = 'Necroborg!'
AND stats.short_name = 'atk'
)
MYSQL insert from select:
http://dev.mysql.com/doc/refman/5.1/en/insert-select.html
The problem is one or both of the following:
There is more than one monster named 'Necroborg!'.
There is more than on stat named 'atk'.
You need to decide what you want to do. One option (mentioned elsewhere) is to use limit 1 to get only one value from each statement.
A second option is to better specify the where clause so you get only one row from each table.
Another is to insert all combinations. You would do this with insert . . . select and a cross join:
INSERT INTO monster_stats(monster_id, stat_id, value)
SELECT m.id, s.id, 2
FROM (SELECT id FROM monsters WHERE name = 'Necroborg!') m CROSS JOIN
(SELECT id FROM stats WHERE short_name = 'atk');
A third possibility is that there is a field connecting the two tables, such as monster_id. But, based on the names of the tables, I don't think that is true.
I'm trying to write a query like
if (select count(*) from Users where fkId=5000 and status='r') =
(select count(*) from Users where fkId=5000) then ..
in just one query.
What this means is, if all the rows that have fkId=5000 also have status=r, then do something.
There can be any number of rows with fkId=5000, and any fraction of those rows could have status=r, status=k, status=l, status=a etc. I'm interested in the case where ALL the rows that have fkId=5000 also have status=r (and not any other status).
The way I'm doing it now is
how many rows with id=5000 and status = 'r'?
how many rows with id=5000?
are those numbers equal? then ..
I'm trying to figure out how to rewrite this query using only 1 query, instead of 2. Keyword ALL didn't seem to be able to write such a query (<> ALL is equivalent to NOT IN). I tried a couple of GROUP BY formulations but could not get the correct result to appear.
The most efficient way to do this is:
if not exists (select 1
from users
where fkid = 5000 and (status <> 'r' or status is null)
)
This will stop the query at the first non-matching row.
I suggest you to check for any rows with status not equal to 'r'
SELECT count(*)>0 FROM Users WHERE fkId = 5000 AND status != 'r'
In the following case, if the number 1 is "true" (which it is) then you'll get Yes back, and if not you'll get No back:
SELECT IF(1, 'Yes', 'No') AS yesorno
(Go ahead -- try it!)
In your case however, the following would be more appropriate:
SELECT IF (
(SELECT COUNT(*) FROM Users WHERE fkId=5000 AND status IN('r') AND status NOT IN('1', 'a', 'k')) = (SELECT COUNT(*) FROM Users WHERE fkId=5000),
'They are equal.',
'They are not equal.'
)
AS are_they_equal
By adding AS, you can manipulate the name of the "column" that's returned to you.
Hope that helps... Also, see this page if you'd like more info.
:)
EASY!
Simply join back to the same table. Here is the complete code for testing:
CREATE TABLE Users(id int NOT NULL AUTO_INCREMENT, fkID int NOT NULL, status char(1), PRIMARY KEY (id));
INSERT Users (fkID, status) VALUES (5000, 'r');
INSERT Users (fkID, status) VALUES (5000, 'r');
INSERT Users (fkID, status) VALUES (5000, 'r');
-- The next query produces "0" to indicate no miss-matches
SELECT COUNT(*) FROM Users u1 LEFT JOIN Users u2 ON u1.id=u2.id AND u2.status='r' WHERE u1.fkID=5000 AND u2.id IS NULL;
-- now change one record to create a miss-match
UPDATE Users SET status='l' WHERE id=3 ;
-- The next query produces "1" to indicate 1 miss-match
SELECT COUNT(*) FROM Users u1 LEFT JOIN Users u2 ON u1.id=u2.id AND u2.status='r' WHERE u1.fkID=5000 AND u2.id IS NULL;
DROP TABLE Users;
So all you need to test for in the result is that it's 0 (zero) meaning everything has fkID=5000 also has status='r'
If you properly index your table then joining back to the same table is not an issue and certainly beats having to do a 2nd query.
Besides the NOT EXISTS version - which should be the most efficient as it does no counting at all and exits as soon as it finds a value that doesn't match the conditions, there is one more way, that will work if status is not nullable and will be efficient if there is an index on (fkId, status):
IF EXISTS
( SELECT 1
FROM Users
WHERE fkId = 5000
HAVING MIN(status) = 'r'
AND MAX(status) = 'r'
)
There is one difference though. The above will show false if there are no rows at all with fkId=5000, while the NOT EXISTS version will show true - which is probably what you want anyway.
I have this MySQL tables:
station (id, name)
station_track (id, id_station, id_track)
track (id, name)
and I'd like to get all the tracks that contains station A and station B... I just can't figure it out :S I tried like this:
SELECT track.name
FROM track, station_track , station
WHERE station.id = station_track.id_station
AND track.id = station_track.id_track
AND (station.name = 'first' AND station.name = 'second')
It doesn't work... I guess I can't use AND for same column values.
SOLVED:
SELECT proge.ime FROM postaje, postaje_proge, proge
WHERE postaje.id=postaje_proge.ID_postaje AND proge.ID=postaje_proge.ID_proge
AND postaje.ime_postaje in ("AP Mlinska","City Center")
GROUP BY proge.ime
HAVING count(proge.ime)=2
tnxx guys for help!
Your final condition, (station.name="first" AND station.name="second"), is checking that one variable is equal to two different values at the same time which will never evaluate to true.
If you want to find all stations with the names first or second, you need to use an OR statement.
SELECT track.name FROM track, station_track , station
WHERE station.id=station_track.id_station
AND track.id=station_track.id_track
AND (station.name="first" OR station.name="second")
Assuming you want tracks linked to both stations A and B, try:
SELECT t.name
FROM track t
JOIN station_track st on t.id=st.id_track
JOIN station s on s.id=st.id_station and s.name in ('first','second')
GROUP BY t.name
HAVING count(distinct s.name)=2
You will have to do a bit of thinking and redesign your tables. If you want to match a field to a list of values you can use the 'in' operative
i.e
SELECT * FROM station_track WHERE id_track in (1, 2, 3, 4);
The above will return all records matching any of the values in the list. So, think about how you could take advantage of this and redesign your schema.
I have a table with a composite key composed of 2 columns, say Name and ID. I have some service that gets me the keys (name, id combination) of the rows to keep, the rest i need to delete. If it was with only 1 row , I could use
delete from table_name where name not in (list_of_valid_names)
but how do I make the query so that I can say something like
name not in (valid_names) and id not in(valid_ids)
// this wont work since they separately dont identity a unique record or will it?
Use mysql's special "multiple value" in syntax:
delete from table_name
where (name, id) not in (select name, id from some_table where some_condition);
If your list is a literal list, you can still use this approach:
delete from table_name
where (name, id) not in (select 'john', 1 union select 'sally', 2);
Actually, no I retract my comment about needing special juice or being stuck with (AND OR'ing all your options).
Since you have a list of values of what you want to retain, dump that into a temporary table. Then do a delete against the base table for what does not exist in the temporary table (left outer join). I suck at mysql syntax or I'd cobble together your query. Psuedocode is approximate
DELETE
B
FROM
BASE B
LEFT OUTER JOIN
#RETAIN R
ON R.key1 = B.key1
AND R.key2 = B.key
WHERE
R.key1 IS NULL
The NOT EXISTS version:
DELETE
b
FROM
BaseTable b
WHERE
NOT EXISTS
( SELECT
*
FROM
RetainTable r
WHERE
(r.key1, r.key2) = (b.key1, b.key2)
)