I'm trying to get a total count of all the rows in a table which have duplicates.
Here is the query I am using right now:
SELECT count( `id_lead` )
FROM `lead_history`
GROUP BY `id_lead`
HAVING count( * ) > 1
The problem is that this isn't counting the total number of rows, it is counting the total amount of times each row contains a duplicate and returning that.
So right now, it is returning like this:
2
4
6
2
Given those results, I actually want my query to return 4, since there are 4 rows which have duplicates. The amount of duplicates each row has does not matter to me.
How would I write this query without using subqueries?
If you were using something like Oracle or SQL Server, you could take advantage of analytic functions. But MySQL does not have these, so using a subquery might the best way to get your answer.
SELECT COUNT(*)
FROM `lead_history`
WHERE `id_lead` IN (SELECT `id_lead` FROM `lead_history` GROUP BY `id_lead` HAVING COUNT(*) > 1)
Note that the subquery is not correlated, so the query optimizer should be able to make this run reasonably efficiently.
Try this way
SELECT COUNT(*)
FROM `lead_history` as b
join (SELECT `id_lead` FROM `lead_history` GROUP BY `id_lead` HAVING COUNT(*) > 1) a on b.id_lead=a.id_lead
Try This
SELECT count( * )
FROM `lead_history`
GROUP BY `id_lead`
HAVING count( * ) > 1
You're almost there, just put your query in a derived table and select the count from that. No additional in or join needed:
select count(*) from (
select `id_lead`
from `lead_history`
group by `id_lead`
having count(*) > 1
) t
Related
I want to select all the matching results in a database table with also random results but with the matching results being at the top. With the way, I am doing now I am using two queries first one being the matching query, and if the count is zero I now select random results. I would like to do this with just one query.
You could attempt using a UNION ALL query as follows.
select product_name,price
from marketing_table
where price >=5000 /*user supplied filter*/
and price <=10000 /*user supplied filter*/
union all
select m.product_name,m.price
from marketing_table m
where not exists (select *
from marketing_table m1
where m1.price >=5000 /*user supplied filter*/
and m1.price <=10000 /*user supplied filter*/
)
What I understand from you comment, you may try something simple like this first:
SET #product := 'purse'; -- search term
SELECT * FROM product
ORDER BY product_name LIKE CONCAT('%',#product,'%') DESC, price ASC;
This is the simplest I can think of and it could be a starting point for you.
Here's a demo : https://www.db-fiddle.com/f/31jrR27dFJqYQQigzBqLcs/2
If this is not what you want, you have to edit your question and insert some example data with expected output. Your current question tend to be flagged as too broad and need focus/clarity.
Did you try using a UNION subquery with a LIMIT?
SELECT *
FROM (
SELECT 0 priority, t.*
FROM first_table t
UNION ALL
SELECT 1 priority, t.*
FROM second_table t
)
ORDER BY priority
LIMIT 20
If you do not want to include any second_table records if first_table returns, you would need to do a subquery on the second query to confirm that no rows exist.
SELECT *
FROM (
SELECT 0 priority, t.*
FROM first_table t
UNION ALL
SELECT 1 priority, t.*
FROM second_table t
LEFT JOIN (SELECT ... FROM first_table) a
WHERE a.id IS NULL
)
ORDER BY priority
LIMIT 20
I think it would be possible to use the Common Table Expressions (CTE) feature in MySQL 8, if you are using that version.
https://dev.mysql.com/doc/refman/8.0/en/with.html
I have a query with a count with some group by, and I want to get the greater count. I can do with an order by and limit 1, but I have multiple results with the same count and then does not work for me.
How do I solve this problem?
With MySql 8+, you can use CTE to get the maximum count, and then retrieve all records with a count equal to the maximum count.
However, since CTE is not available in MySql 5.6, you'd need to use a sub-query to get the maximum count, and then write the main query which compares the count of each record to the maximum count retrieved in the subquery.
Here is a query I wrote. Maybe it's not the most efficient solution, but it gets the desired result.
SELECT
group_id, COUNT(record_id) c
FROM
table_name
GROUP BY group_id
HAVING c IN (
SELECT
MAX(sub_query.c)
FROM
(SELECT
group_id, COUNT(record_id) c
FROM
table_name
GROUP BY group_id) AS sub_query
)
If you are not going to do this using window functions, you can do:
SELECT group_id, COUNT(*) as cnt
FROM table_name
GROUP BY group_id
HAVING cnt = (SELECT COUNT(*)
FROM table_name
GROUP BY group_id
ORDER BY COUNT(*) DESC
LIMIT 1
) ;
I would like to select multiply conditions using below query:
SELECT (SELECT count(*)
FROM users
)
as totalusers,
(SELECT sum(cashedout)
FROM users
) AS cashedout,
(SELECT COUNT(*)
FROM xeon_users_rented
) AS totalbots,
(SELECT sum(value)
FROM xeon_stats_clicks
WHERE typ='3' OR typ='1'
) AS totalclicks
The above query takes just under a second (0.912 to be exact) to execute. This slows things down a lot with thousands of requests.
What seems logical for me is this approach:
SELECT (SELECT count(*), sum(cashedout)
FROM users
)
as totalusers, cashedout,
(SELECT COUNT(*)
FROM xeon_users_rented
) AS totalbots,
(SELECT sum(value)
FROM xeon_stats_clicks
WHERE typ='3' OR typ='1'
) AS totalclicks
However that doesn't work, as I get the following error:
#1241 - Operand should contain 1 column(s)
Furthermore, how can I join the two other tables "xeon_users_rented" and "xeon_stats_clicks" in my first query?
It's slow because you have multiple subqueries. Try using joins instead.
Also, a list of your tables, columns would help us better assist you.
Your 2nd query is using wrong syntax, it should be
SELECT
count(*) as totalusers,
sum(cashedout) cashedout,
(SELECT COUNT(*) FROM xeon_users_rented) AS totalbots,
(SELECT sum(value) FROM xeon_stats_clicks
WHERE typ='3' OR typ='1') AS totalclicks
FROM users
This following query take 1-2 seconds for querying.
SELECT updated, COUNT( * ) count
FROM v2_subscription
WHERE ss_id IN (SELECT MAX(ss_id) ss_id FROM v2_subscription GROUP BY uid, card_id)
while the subquery do take only few milliseconds.
SELECT MAX(ss_id) ss_id FROM v2_subscription GROUP BY uid, card_id
I do have index on uid, card_id and both uid, card_id
It's my sql and i have no idea how to optimize this.
Please advise,
Try this, May be it would help, let me know, if it does.
SELECT a.updated, COUNT( * ) count
FROM v2_subscription a
inner join v2_subscription b
on a.ss_id = max(b.ss_id)
GROUP BY b.uid, b.card_id
Or perhaps this
SELECT a.updated, COUNT( * ) count
FROM v2_subscription a
inner join v2_subscription b
on a.ss_id = (SELECT MAX(b.ss_id) b.ss_id FROM v2_subscription b GROUP BY b.uid, b.card_id)
Finally i have found the solution beside #arkumar above answer.
Adding "ORDER BY ss_id" inside the subquery also do the trick
Since without order by, the result of subquery do not have index.
I'd like to list all rows having a match on same table.
So far i have came up with this
SELECT *
FROM parim_firms
WHERE firm_name IN (
SELECT firm_name
FROM parim_firms
GROUP BY firm_name
HAVING COUNT(*) > 1
)
But this query keeps running, although the subquery itself runs in 0.1 sec.
How could i optimize this?
I think the subquery executes for each row, not only once. Am i right?
how about joining it?
SELECT a.*
FROM parim_firms a
INNER JOIN
(
SELECT firm_name
FROM parim_firms
GROUP BY firm_name
HAVING COUNT(*) > 1
) b ON a.firm_name = b.firm_name
PS: be sure to add index on column firm_name for faster execution.