i have 3 rows on "Services" table:
ID | name | ObrID
0 | A | 1
1 | B | 2
2 | C | -1
-1 is a none existing Obr, the service 2 doesn't contains any Obr or it was deleted.
if i fetch with select * from Services, it works as expected, but if i do my search sql:
select
*,
(select Name from Obrs where ID=ObrID) as ObrName
from
Services
where
(select Name from Obrs where ID=ObrID) like '%SEARCH_STRING%'
it doesn't return the last line. Is there any way so it return something like:
ID | name | ObrID | ObrName
0 | A | 1 | ObrA
1 | B | 2 | ObrB
3 | C | -1 | NULL
You want to use left join.
http://www.tizag.com/mysqlTutorial/mysqlleftjoin.php
SELECT s.*,o.ObrName from Services s
LEFT JOIN Obrs o ON ID=ObrID
WHERE OrbName LIKE '%$SEARCH_STRING%' OR OrbName IS NULL
or:
SELECT * FROM (select s.*,o.ObrName from Services s
LEFT JOIN Obrs o ON ID=ObrID) tmp
WHERE OrbName LIKE '%$SEARCH_STRING%' OR OrbName IS NULL
May be below can help:
select s.*,ob.Name from Services as s left join Obrs as ob on s.ID=ob.ObrID where ob.Name like '%$SEARCH_STRING%';
If there is no Obrs.Name because your ObrID is -1, then Obrs.Name will be NULL and therefor not LIKE '%$SEARCH_STRING%'. You can add an additional condition to also include these cases:
where
(select Name from Obrs where ID=ObrID) like '%$SEARCH_STRING%'
OR ObrID = -1
And follow Flöcsy's suggestion and use a LEFT JOIN. Joins are always the preferred method, especially vs. correlated subquerys. The working condition when using a LEFT JOIN is
WHERE
Obrs.Name LIKE '%$SEARCH_STRING%'
OR Obrs.Name IS NULL
Related
I want to get MIN price from the below tables using RIGHT JOIN and WHERE price not equal to zero and not empty based on user id. How I can get single record with MIN price based on user id in single MYSQL query.
Here is my query with just right join.
SELECT *
FROM SEARCH
RIGHT JOIN offers ON search.search_id=offers.search_id
WHERE search.user_id='1'
table name: search
search | search_id | user_id | datetime
1 | 1 | 1 | -
table name: offer
offer_id | search_id | price
1 | 1 |
2 | 1 | 0
3 | 1 | 506.1
4 | 1 | 285.3
Query will be :
SELECT *
FROM SEARCH
RIGHT JOIN offers ON search.search_id=offers.search_id
WHERE search.user_id='1' AND search.price > 0
ORDER BY search.price ASC LIMIT 1
An alternative using a different join condition:
SELECT MIN(o.price) min_price
FROM search s
JOIN offers o ON (
s.search_id = o.search_id
AND o.price IS NOT NULL
AND o.price > 0
)
WHERE s.user_id = '1'
When you want to select the minimal price, you can use the MYSQL "MIN" function. For this function you need a GROUP BY in your query.
Something like this, just edit it to your requirements.
SELECT *, MIN(price) as `minPrice`
FROM SEARCH
RIGHT JOIN offers ON search.search_id=offers.search_id
WHERE search.user_id='1' AND search.price > 0
GROUP BY search.search_id
I have two tables, one is an index (or map) which helps when other when pulling queries.
SELECT v.*
FROM smv_ v
WHERE (SELECT p.network
FROM providers p
WHERE p.provider_id = v.provider_id) = 'RUU='
AND (SELECT p.va
FROM providers p
WHERE p.provider_id = v.provider_id) = 'MjU='
LIMIT 1;
Because we do not know the name of the column that holds the main data, we need to look it up, using the provider_id which is in both tables, and then query.
I am not getting any errors, but also no data back. I have spent the past hour trying to put this on sqlfiddle, but it kept crashing, so I just wanted to check if my code is really wrong, hence the crashing?
In the above example, I am looking in the providers table for column network, where the provider_id matches, and then use that as the column on smv.
I am sure i have done this before just like this, but after the weekend trying I thought i would ask on here.
Thanks in Advance.
UPDATE
Here is an example of the data:
THis is the providers, this links so no matter what the name of the column on the smv table, we can link them.
+---+---+---------------+---------+-------+--------+-----+-------+--------+
| | A | B | C | D | E | F | G | H |
+---+---+---------------+---------+-------+--------+-----+-------+--------+
| 1 | 1 | Home | network | batch | bs | bp | va | bex |
| 2 | 2 | Recharge | code | id | serial | pin | value | expire |
+---+---+---------------+---------+-------+--------+-----+-------+--------+
In the example above, G will mean in the smv column for recharge we be value. So that is what we would look for in our WHERE clause.
Here is the smv table:
+---+---+-----------+-----------+---+----+---------------------+-----+--+
| | A | B | C | D | E | F | value | va |
+---+---+-----------+-----------+---+----+---------------------+-----+--+
| 1 | 1 | X2 | Home | 4 | 10 | 2016-09-26 15:20:58 | | 7 |
| 2 | 2 | X2 | Recharge | 4 | 11 | 2016-09-26 15:20:58 | 9 | |
+---+---+-----------+-----------+---+----+---------------------+-----+--+
value in the same example as above would be 9, or 'RUU=' decoded.
So we do not know the name of the rows, until the row from smv is called, once we have this, we can look up what column name we need to get the correct information.
Hope this helps.
MORE INFO
At the point of triggering, we do not know what the row consists of the right data because some many of the fields would be empty. The map is there to help we query the right column, to get the right row (smv grows over time depending on whats uploaded.)
1) SELECT p.va FROM providers p WHERE p.network = 'Recharge' ;
2) SELECT s.* FROM smv s, providers p WHERE p.network = 'Recharge';
1) gives me the correct column I need to look up and query smv, using the above examples it would come back with "value". So I need to now look up, within the smv table, C = Recharge, and value = '9'. This should bring me back row 2 of the smv table.
So individually both 1 and 2 queries work, but I need them put together so the query is done on the database server.
Hope this gives more insight
Even More Info
From reading other posts, which are not really doing what I need, i have come up with this:
SELECT s.*
FROM (SELECT
(SELECT p.va
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS net,
(SELECT p.bex
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS bex
FROM dh_smv_providers) AS val, dh_smv_ s
WHERE s.provider_id = 'vodaphone' AND net = '20'
ORDER BY from_base64(val.bex) DESC;
The above comes back blank, but if i replace net, in the WHERE clause with a column I know exists, I do get the results expected:
SELECT s.*
FROM (SELECT
(SELECT p.va
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS net,
(SELECT p.bex
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS bex
FROM dh_smv_providers) AS val, dh_smv_ s
WHERE s.provider_id = 'vodaphone' AND value = '20'
ORDER BY from_base64(val.bex) DESC;
So what I am doing wrong, which is net, not showing the value derived from the subquery "value" ?
Thanks
SELECT
v.*,
p.network, p.va
FROM
smv_ v
INNER JOIN
providers p ON p.provider_id = v.provider_id
WHERE
p.network = 'RUU=' AND p.va = 'MjU='
LIMIT 1;
The tables talk to each other via the JOIN syntax. This completely circumvents the need (and limitations) of sub-selects.
The INNER JOIN means that only fully successful matches are returned, you may need to adjust this type of join for your situation but the SQL will return a row of all v columns where p.va = MjU and p.network = RUU and p.provider_id = v.provider_id.
What I was trying to explain in comments is that subqueries do not have any knowledge of their outer query:
SELECT *
FROM a
WHERE (SELECT * FROM b WHERE a)
AND (SELECT * FROM c WHERE a OR b)
This layout (as you have in your question) is that b knows nothing about a because the b query is executed first, then the c query, then finally the a query. So your original query is looking for WHERE p.provider_id = v.provider_id but v has not yet been defined so the result is false.
I have a table called FieldList that looks like this:
ElementName|Description|comp_id|FieldName
-----------------------------------------
Name | red | 1 | names
Name | blue | 7 | names
field | red | 1 | names
boxes | blue | 5 | blues
field | orange | 7 | reds
And I want to show a new table that shows only the ElementNames that are the same and then show which comp_id they belong to so it looks like this:
ElementName| comp_id| comp_id
-----------------------------
Name | 1 | 7
field | 1 | 7
It doesnt have to look exactly like this but the point is I want to be able to join and show the ElementNames that are identical but have different comp_id's.
This is the little bit of sql code that I have already but its obviously not working.
SELECT a.comp_id, a.ElementName, b.ElementName
FROM FieldList a
INNER JOIN FieldList b ON a.ElementName = b.ElementName;
You seem to want element names that have the same comp ids. If so, you can use group_concat() like this:
select group_concat(elementname), comps
from (select fl.elementname, group_concat(fl.comp_id order by fl.comp_id) as comps
from fieldlist fl
group by fl.elementname
) en
group by comps;
This actually produces rows with two lists:
Name,field 1,7
But it seems to contain the information you want.
This query may accomplish what you want:
SELECT a.ElementName, a.comp_id, b.comp_id
FROM FieldList a
JOIN FieldList b ON a.ElementName = b.ElementName
WHERE a.comp_id != b.comp_id
GROUP BY a.ElementName, (a.comp_id + b.comp_id);
Note that I am grouping by the addition of the two comp_ids. If I didn't, you wouldn't get rows for each duplication.
Try this...
SELECT a.ElementName, a.comp_id, b.comp_id
From FieldList a
left join FieldList b on
a.ElementName = b.ElementName and
a.comp_id <> b.comp_id
WHERE a.comp_id is not null
I need to implement a function which returns all the networks the installation is not part of.
Following is my table and for example if my installation id is 1 and I need all the network ids where the installation is not part of then the result will be only [9].
network_id | installation_id
-------------------------------
1 | 1
3 | 1
2 | 1
2 | 2
9 | 2
2 | 3
I know this could be solved with a join query but I'm not sure how to implement it for the same table. This is what I've tried so far.
select * from network_installations where installation_id = 1;
network_id | installation_id
-------------------------------
1 | 1
2 | 1
3 | 1
select * from network_installations where installation_id != 1;
network_id | installation_id
-------------------------------
9 | 2
2 | 2
2 | 3
The intersection of the two tables will result the expected answer, i.e. [9]. But though we have union, intersect is not present in mysql. A solution to find the intersection of the above two queries or a tip to implement it with a single query using join will be much appreciated.
The best way to do this is to use a network table (which I presume exists):
select n.*
from network n
where not exists (select 1
from network_installation ni
where ni.network_id = n.network_id and
ni.installation_id = 1
);
If, somehow, you don't have a network table, you can replace the from clause with:
from (select distinct network_id from network_installation) n
EDIT:
You can do this in a single query with no subqueries, but a join is superfluous. Just use group by:
select ni.network_id
from network_installation ni
group by ni.network_id
having sum(ni.installation_id = 1) = 0;
The having clause counts the number of matches for the given installation for each network id. The = 0 is saying that there are none.
Another solution using OUTER JOIN:
SELECT t1.network_id, t1.installation_id, t2.network_id, t2.installation_id
FROM tab t1 LEFT JOIN tab t2
ON t1.network_id = t2.network_id AND t2.installation_id = 1
WHERE t2.network_id IS NULL
You can check at http://www.sqlfiddle.com/#!9/4798d/2
select *
from network_installations
where network_id in
(select network_id
from network_installations
where installation_id = 1
group by network_id )
I have 3 tables: questions, options, comments_to_options(opt_comments).
I want to write a query that returns in each row the following values, concatenated:
A question, all options to it, all comments to each option.
My query is:
select
concat('{', '"qid":"', q.q_id, '", "qt":"', q.q_title,
'", "op":[', group_concat('{"oi":"', o.op_id, '", "ot":"', o.opt_value, '", ', oc_list, '}'
order by o.opt_upvotes desc), ']}')
as r
from questions q, options o,
(select o.op_id as ocid, concat('"oc":[', group_concat('{"oci":"', oc.opt_com_id, '", "occ":"', oc.opt_com_value, '"}'
order by oc.opt_com_added_at), ']')
as oc_list
from options o, opt_comments oc
where oc.opt_com_to=o.op_id
group by o.op_id)
as r2
where o.op_id=r2.ocid
and q.q_id=o.option_to
group by q.q_id
order by q.q_added_at desc
limit 3;
But the above query gives only those options that have at least one comment to them.
How should I modify?
You are using the old JOIN syntax with comma-separated lists of tables and subqueries. That syntax is correct, but generates INNER JOIN operations. Such joins suppress rows that don't match the join criterion.
You need to adopt the LEFT JOIN syntax. Without refactoring your entire query, I will say that you should change
FROM a,
(select something from z) AS b
WHERE a.value=b.value
to
FROM a
LEFT JOIN (select something from z) AS b ON a.value=b.value
Also, beware, you may encounter the character-string length limit in GROUP_CONCAT(). Read this:
MySQL and GROUP_CONCAT() maximum length
Use "left join".
Example:
create table opt (oid int,name varchar(100));
insert into opt values (1,'opt1');
insert into opt values (2,'opt2');
insert into opt values (3,'opt3');
create table optcom (oid int,com varchar(100));
insert into optcom values (1,'opt1_1');
insert into optcom values (1,'opt1_2');
insert into optcom values (3,'opt3_1');
When using "simple join":
select opt.*,optcom.* from opt join optcom on opt.oid=optcom.oid;
+------+------+------+--------+
| oid | name | oid | com |
+------+------+------+--------+
| 1 | opt1 | 1 | opt1_1 |
| 1 | opt1 | 1 | opt1_2 |
| 3 | opt3 | 3 | opt3_1 |
+------+------+------+--------+
When "left join":
select opt.*,optcom.* from opt left join optcom on opt.oid=optcom.oid;
+------+------+------+--------+
| oid | name | oid | com |
+------+------+------+--------+
| 1 | opt1 | 1 | opt1_1 |
| 1 | opt1 | 1 | opt1_2 |
| 2 | opt2 | NULL | NULL |
| 3 | opt3 | 3 | opt3_1 |
+------+------+------+--------+
To follow up on the above responses, the SQL amended to use outer joins:-
SELECT CONCAT('{', '"qid":"', q.q_id, '", "qt":"', q.q_title,'", "op":[', GROUP_CONCAT('{"oi":"', o.op_id, '", "ot":"', o.opt_value, '", ', oc_list, '}' ORDER BY o.opt_upvotes DESC), ']}') AS r
FROM options o
LEFT OUTER JOIN questions q
ON q.q_id = o.option_to
LEFT OUTER JOIN
(
SELECT o.op_id AS ocid,
CONCAT('"oc":[', GROUP_CONCAT('{"oci":"', oc.opt_com_id, '", "occ":"', oc.opt_com_value, '"}' ORDER BY oc.opt_com_added_at), ']') AS oc_list
FROM options o
INNER JOIN opt_comments oc
ON oc.opt_com_to=o.op_id
GROUP BY o.op_id
) r2
ON o.op_id = r2.ocid
GROUP BY q.q_id
ORDER BY q.q_added_at DESC
LIMIT 3;
Looking at this I am unsure about the join to the sub query. This appears to be bringing back an encoded string, but beyond the actual join nothing from this sub query is actually used.
As such I am unsure if that sub query is just being used to narrow down the rows returned (in which case joining against it using an INNER JOIN would be appropriate - and you may as well not bring back the encoded string), or if you have posted a cut down version of the query that you have been trying to debug.