I am trying to perform a query which groups a set of data by an attribute called type_id.
SELECT
vt.id AS voucher_type,
COALESCE(COUNT(v.id), 0) AS vouchers_remaining
FROM
vouchers v
INNER JOIN voucher_types vt
ON vt.id = v.type_id
WHERE
v.sold = 0
GROUP BY vt.id
What I want in the result is the type_id and the number of unsold products remaining for each type. This is working OK provided that there is at least one left, however if there is a zero count row, it is not returned in the result set.
How can I set up a dummy row for those types which do not have any corresponding rows to count?
Any advice would be greatly appreciated.
Thanks
You'll have to use a LEFT JOIN instead of an INNER JOIN. You start by selecting all voucher_types and then left join to find the count.
SELECT
voucher_types.id AS voucher_type,
IFNULL(vouchers_count.vouchers_remaining, 0) AS vouchers_remaining
FROM
voucher_types
LEFT JOIN
(
SELECT
v.type_id AS voucher_type,
COUNT(v.id) AS vouchers_remaining
FROM
vouchers v
WHERE
v.sold = 0
GROUP BY v.type_id
) AS vouchers_count
ON vouchers_count.voucher_type = voucher_types.id
You want an OUTER JOIN (or LEFT JOIN, same difference) instead of an INNER JOIN. That should already do the trick.
Because you're doing an INNER JOIN you automatically exclude types with no corresponding vouchers. You need a RIGHT OUTER JOIN.
Also, as far as I can remember, COUNT will always give you an integer, so there is no need for the COALESCE.
Good luck,
Alin
Related
I have the next results from a query. I did this:
Where the user "Adriana Smith" with ID 6 is repeated because she has different contract dates, to do that I did a left join from table bo_users to bo_users_contracts (1:m One to Many Relation). The query is below:
SELECT bo_users.ID, bo_users.display_name, COALESCE (bo_users_contracts.contract_start_date,'-') AS contract_start_date, COALESCE (bo_users_contracts.contract_end_date, '-') AS contract_end_date, COALESCE (bo_users_contracts.current,'-') AS current
FROM bo_users
LEFT JOIN bo_users_contracts ON bo_users.ID = bo_users_contracts.bo_users_id
LEFT JOIN bo_usermeta ON bo_users.ID = bo_usermeta.user_id
WHERE (bo_usermeta.meta_key = 'role' AND bo_usermeta.meta_value = 'member')
But I want to get all users, but from user Adriana I just want to get the occurrence where "current" column = 1.
So the final result would be the 3 user's records:
Alejandro, Rhonda and Adriana (with "current" = 1)
Thank you!
Since you want to limit on a table being outer joined, the limit should be placed on the join itself so the all records from bo_users is retained. (as indicated desired by the outer join)
Essentially the limit is applied before the join so the unmatched records from BO_users to bo_users_contracts are kept. If applied after the join in a where clause the records from BO_user without a matching record would have a null value for current and thus be excluded when the current=1 filter is applied.
In this example the only values which should be in the where would be from table BO_USERS.
I'd even move the bo_usermeta filters to the join or you may lose bo_users; or the left join on the 3rd table should be an inner join.
SELECT bo_users.ID
, bo_users.display_name
, COALESCE (bo_users_contracts.contract_start_date,'-') AS contract_start_date
, COALESCE (bo_users_contracts.contract_end_date, '-') AS contract_end_date
, COALESCE (bo_users_contracts.current,'-') AS current
FROM bo_users
LEFT JOIN bo_users_contracts
ON bo_users.ID = bo_users_contracts.bo_users_id
and bo_users_contracts.current = 1
LEFT JOIN bo_usermeta --This is suspect
ON bo_users.ID = bo_usermeta.user_id
WHERE (bo_usermeta.meta_key = 'role' --this is suspect
AND bo_usermeta.meta_value = 'member') --this is suspect
The lines reading this is suspect are that way because you have a left join which means you want all users from bo_users.. However if a user doesn't have a meta_key or meta_value defined, they would be eliminated. Either change the join to an inner join or move the where clause limits to the join. I indicate this as you're query is "inconsistent" in it's definition leading to ambiguity when later maintained.
I am trying to perform the following query:
SELECT wwpqsr.statistic_ref_id,
wwpqsr.create_time,
wwpqm.name
FROM wp_wp_pro_quiz_statistic_ref AS wwpqsr
INNER JOIN wp_wp_pro_quiz_statistic AS wwpqs
ON ( wwpqs.statistic_ref_id = wwpqsr.statistic_ref_id
AND COUNT(wwpqs.correct_count) AS correct =
COUNT(wwpqs.incorrect_count) AS incorrect)
INNER JOIN wp_wp_pro_quiz_master AS wwpqm
ON (wwpqm.id = wwpqsr.quiz_id)
WHERE wwpqsr.user_id = 1;
I need to do a limit on the result here at the end, that is not being shown right now for functionality purposes, since I need to only get results returned from the p_wp_pro_quiz_statistic table where the count of correct_count equals the count of rows from the incorrect_count column. How can I do this within an INNER JOIN here? All within 1 query? Possible? The above code returns empty result, where it should not be an empty result. How should something like this be done?
As I said in comments, you can't use aggregate functions as a where clause unless it is a field from a subquery. For your case I think you are looking for:
SELECT wwpqsr.statistic_ref_id,
wwpqsr.create_time,
wwpqm.name
FROM wp_wp_pro_quiz_statistic_ref AS wwpqsr
INNER JOIN wp_wp_pro_quiz_statistic AS wwpqs
ON ( wwpqs.statistic_ref_id = wwpqsr.statistic_ref_id )
INNER JOIN wp_wp_pro_quiz_master AS wwpqm
ON (wwpqm.id = wwpqsr.quiz_id)
WHERE wwpqsr.user_id = 1
GROUP
BY wwpqsr.statistic_ref_id,
wwpqsr.create_time,
wwpqm.name
HAVING COUNT(wwpqs.correct_count) = COUNT(wwpqs.incorrect_count);
I have 3 tables
movies_detais
movies_revies
movies_gossips
What I want is that I want all the data whose movies_relesed_type=0 and movies_type=1
But I am not getting desired values
Code
Select md.movies_name,
md.movies_description,
mr.rt_user_comments,
mg.gossip_desc
from movies_details md
Inner join movies_reviews mr
on md.movies_id=mr.movie_review_id
Inner join movies_gossips mg
on md.movies_id=mg.movies_gossip_id
and md.movie_relesed_type='0'
and md.movie_type='1'
With this code I am only getting one row whose movies_relesed_type=0 and movies_type=1, but in my table I am having other rows also which meets the condition but they are not displaying.
I think this is a case where you want the conditions in the where clause:
Select md.movies_name,
md.movies_description,
mr.rt_user_comments,
mg.gossip_desc
from movies_details md Inner join
movies_reviews mr
on md.movies_id=mr.movie_review_id left join
movies_gossips mg
on md.movies_id = mg.movies_gossip_id
where md.movie_relesed_type='0' and md.movie_type = '1';
A left outer join returns all the rows from the first table, even when the condition in the on clause evaluates to not-true. This is true regardless of which table the conditions refer to. So, you cannot filter on the first table in the on clause using a left outer join.
This is my query. The output looks fine except the COUNT function is returning numbers which seem totally arbitrary (e.g. 7-digit numbers where I'd expect 3-digit numbers):
SELECT tc.tableName, m.fieldName, COUNT(m.fieldName)
FROM apiResult, (
SELECT cc.surveyID, cc.fieldName
FROM apiResult as ar
INNER JOIN columnConversion as cc
ON substring(ar.triggerName,-10)=cc.fieldID
) AS m
INNER JOIN tableConversion as tc
ON m.surveyID=tc.surveyID
GROUP BY tc.tableName, m.fieldName;
I think, for a start, that COUNT(m.fieldName) is probably wrong, since it doesn't correspond with GROUP BY tc.tableName, m.fieldName.
Here's what the query is meant to do: one of the tables in the sub-query, apiResult, has a column called 'triggerName' which contains an ID I call 'fieldID', plus a column called 'surveyID'. The tables columnConversion and tableConversion are tables which match the IDs to human readble names. So, the follow query produces the count that I want, but, I want the IDs replaced by the human readable names, hence the above query:
SELECT cc.surveyID, cc.fieldName, COUNT(ar.triggerName)
FROM apiResult as ar
INNER JOIN columnConversion as cc
ON substring(ar.triggerName,-10)=cc.fieldID
GROUP BY (ar.triggerName)
Any ideas what I've done wrong?
Why are you mixing explicit and implicit joins? You appear to have missed a join condition on the first table. Well, actually, I don't think it is needed. This should work:
SELECT tc.tableName, m.fieldName, COUNT(m.fieldName)
FROM (SELECT cc.surveyID, cc.fieldName
FROM apiResult ar INNER JOIN
columnConversion cc
ON substring(ar.triggerName, -10) = cc.fieldID
) m INNER JOIN
tableConversion as tc
ON m.surveyID = tc.surveyID
GROUP BY tc.tableName, m.fieldName;
I have this query...
$sQuery = "
SELECT SQL_CALC_FOUND_ROWS ".str_replace(" , ", " ", implode(", ", $aColumns))."
FROM dominios left join datas on dominios.id_dominio=datas.id_dominio
left join dnss on dominios.id_dominio=dnss.id_dominio
left join entidades_gestoras on dominios.id_dominio=entidades_gestoras.id_dominio
left join estados on dominios.id_dominio=estados.id_dominio
left join ips on dominios.id_dominio=ips.id_dominio
left join quantidade_dnss on dominios.id_dominio=quantidade_dnss.id_dominio
left join responsaveis_tecnicos on dominios.id_dominio=responsaveis_tecnicos.id_dominio
left join titulares on dominios.id_dominio=titulares.id_dominio
WHERE dominios.estado not like 2 and dominios.estado not like 0 AND data_expiracao > '".date("Ymd")."' $sWhere $where
GROUP BY dominio
$sOrder
$sLimit
";
It returns me the results I 'need'...
But the Group By, it show me the first result that appear on the database, and I needed the last...
How can I do this? :s
Edited
This is the final query, without those variables
SELECT SQL_CALC_FOUND_ROWS `datas`.`data_insercao`, `datas`.`data_expiracao`, `datas`.`data_registo`,
`dominios`.`dominio`,
`titulares`.`nome`, `titulares`.`morada`, `titulares`.`email`, `titulares`.`localidade`, `titulares`.`cod_postal`,
`entidades_gestoras`.`nome`, `entidades_gestoras`.`email`,
`responsaveis_tecnicos`.`nome`, `responsaveis_tecnicos`.`email`,
`ips`.`ip`, `dominios`.`id_dominio` FROM dominios left join datas on dominios.id_dominio=datas.id_dominio
left join dnss on dominios.id_dominio=dnss.id_dominio
left join entidades_gestoras on dominios.id_dominio=entidades_gestoras.id_dominio
left join estados on dominios.id_dominio=estados.id_dominio
left join ips on dominios.id_dominio=ips.id_dominio
left join quantidade_dnss on dominios.id_dominio=quantidade_dnss.id_dominio
left join responsaveis_tecnicos on dominios.id_dominio=responsaveis_tecnicos.id_dominio left join titulares on dominios.id_dominio=titulares.id_dominio WHERE dominios.estado not like 2 and dominios.estado not like 0 AND data_expiracao > '20120730' GROUP BY dominio ORDER BY `datas`.`data_insercao` asc LIMIT 0, 10
General considerations
I'm not sure what columsn you have in aColumns, or what table that dominio column comes from. When you group a number of rows using GROUP BY, then the columns you select for your result should either have the same value for all rows of the group (i.e. be functionally dependent), or should be some aggregate function combining the values of all the rows in the group.
Some SQL dialects enforce this. MySQL doesn't, but if you select an unaggregated column which has different values within the group, there are no guarantees as to what value will actually be returned to you. It might come from any row within the group. So there is no way to get the “last” of these rows, as there isn't any inherent order. In simple cases you can use MIN or MAX to select the value you need. In more complicated cases, you'll most likely have to use subqueries to do the selection from within the groups.
For example, this answer computes for every Name (which corresponds to your dominio grouping column) the last value of Action based on an ordering by ascending Time. Or rather the first value using a descending ordering, which is the same.
Your application
As your comment below indicates that you want the maximal id_dominio for each dominio in dominios, I suggest the following:
SELECT …
FROM (SELECT MAX(id_dominio) AS id_dominio
FROM dominios
GROUP BY dominio
WHERE estado <> 2
AND estado <> 0
) domIds
LEFT JOIN datas ON domIds.id_dominio=datas.id_dominio
…
So there will be one subquery to compute the maximal id_dominio for each dominio group, and all subsequent joins can use the IDs from that subquery instead of the full dominio table. If you need other columns from the dominio table as well, you might have to include that in the join again, so that you can get all the values from those row3s whose IDs you selected in the subquery.
By default MySQL sorts records in ascending order, to get last records first you need to sort the records in DESCNDING ORDER:
$sOrder DESC