I read few articles about this: Select max date, then max time This one seems most helpful but I do not see way to implement it.
There is five tables. I join them. I need to select only one row with highest date and highest time from first table and same from second table and join the rest on some other value. With the code I wrote I get multiple rows. It seems time selection is not right.
It might be done with subquery in subquery. I've tried something like this:
SELECT * from table1
INNER JOIN table2 ON table1.date = table2.date AND table1.gm = table2.gm
INNER JOIN table3 ON table2.gm = table3.gm ...
WHERE table3.date = :date AND table4.date = :date ...
AND table1.date IN(
SELECT MAX(table1.date) FROM table1 WHERE table1.time IN(
SELECT MAX(table1.time) FROM table1
)
)
AND table2.date IN(
SELECT MAX(table2.date) FROM table1 WHERE table2.time IN(
SELECT MAX(table2.time) FROM table2 )
)
ORDER BY table1.id
Question is:
How to get single row after joining all of this where date is highest and time is highest on that date?
Thanks!
EDIT: I am sorry for this. I forgot to say that I need max time of max date related with specific value from tables(gm columns). So that is one row(in example I gave it is table1.gm and table2.gm ... ) for each one of that .gm values which are same in every table, not just one row all together. Solutions Nick and Salim provided works but I did not solved problem.
EDIT: SOLVED! after implementing solutions by Nick I just neded to add GROUP BY cntrs_reper.gm_company_no, cntrs_reper.date.
And that's it. For every row in one table enties with highest date and time from others!! Thanks to all.
EDIT. If this can help this is full query:
SELECT cntrs_gm.gm_company_no AS company_c_g,
bns_gms.ded_bns AS ded_bns_gms,
bns_gms.no_ded_bns AS no_ded_bns_gms,
bns_gms.wag_ded_bns AS wag_ded_bns_gms,
cntrs_gm.cur_credit AS cur_credit_c_g,
cntrs_gm.cdrop AS cdrop_c_g,
cntrs_gm.total_jp AS total_jp_c_g,
cntrs_gm.games AS games_c_g,
cntrs_gm.wgames AS wgames_c_g,
cntrs_gm.doors AS doors_c_g,
cntrs_gm.power AS power_c_g,
cntrs_gm.total_in AS total_in_c_g,
cntrs_gm.total_out AS total_out_c_g,
cntrs_gm.total_acc AS total_acc_c_g,
cntrs_gm.total_bet AS total_bet_c_g,
cntrs_gm.total_win AS total_win_c_g,
cntrs_gm.total_bonus AS total_bonus_c_g,
cntrs_gm.date AS date_c_g,
cntrs_reper.gm_company_no AS company_reper,
bns_reper.ded_bns AS ded_bns_reper,
bns_reper.no_ded_bns AS no_ded_bns_reper,
bns_reper.wag_ded_bns AS wag_ded_bns_reper,
cntrs_reper.cur_credit AS cur_credit_reper,
cntrs_reper.cdrop AS cdrop_reper,
cntrs_reper.total_jp AS total_jp_reper,
cntrs_reper.games AS games_reper,
cntrs_reper.wgames AS wgames_reper,
cntrs_reper.doors AS doors_reper,
cntrs_reper.power AS power_reper,
cntrs_reper.total_in AS total_in_reper,
cntrs_reper.total_out AS total_out_reper,
cntrs_reper.total_acc AS total_acc_reper,
cntrs_reper.total_bet AS total_bet_reper,
cntrs_reper.total_win AS total_win_reper,
cntrs_reper.total_bonus AS total_bonus_reper,
cntrs_reper.date AS date_reper,
cntrs_reper.time AS time_reper,
bns_reper.time AS time_c_g,
gms_cfg.gm_no AS machine_id,
gms_cfg.denom_cin AS machine_cin
FROM bns_gms
INNER JOIN cntrs_gm
ON bns_gms.gm_company_no = cntrs_gm.gm_company_no AND bns_gms.date = cntrs_gm.date
INNER JOIN bns_reper
ON cntrs_gm.gm_company_no = bns_reper.gm_company_no
INNER JOIN cntrs_reper
ON bns_reper.gm_company_no = cntrs_reper.gm_company_no AND bns_reper.date = cntrs_reper.date
INNER JOIN gms_cfg
ON cntrs_reper.gm_company_no = gms_cfg.gm_no
WHERE bns_reper.date IN(
SELECT MAX(DATE(bns_reper.date)) FROM bns_reper WHERE bns_reper.time IN(
SELECT MAX(TIME(bns_reper.time)) FROM bns_reper
)
)
AND cntrs_reper.date IN(
SELECT MAX(DATE(cntrs_reper.date)) FROM cntrs_reper WHERE cntrs_reper.time IN(
SELECT MAX(TIME(cntrs_reper.time)) FROM cntrs_reper
)
)
ORDER BY cntrs_gm.gm_company_no
DB example
bns_gms
bns_reper
cntrs_gm
cntrs_reper
gms_cfg
The problem with your current query is that it will select all rows where table1.date is the latest date on which the highest time occurs, which may well be more than one e.g. for data such as
id date time
1 2018-03-30 18:40
2 2018-03-31 12:20
3 2018-03-31 19:20
Your WHERE clause:
table1.date IN(
SELECT MAX(table1.date) FROM table1 WHERE table1.time IN(
SELECT MAX(table1.time) FROM table1
)
will select rows with id=2 and id=3 as they both have date = '2018-03-31' which is when the maximum time occurs.
What you want to do is select the row which has the latest time on the latest date, for which you could use
table1.date = (SELECT MAX(date) FROM table1) AND
table1.time = (SELECT MAX(time) FROM table1 WHERE date = (SELECT(MAX(date) FROM table1))
By using aliasing, that can be simplified (since we already know table1.date = MAX(date) FROM table1) to
table1.date = (SELECT MAX(date) FROM table1) AND
table1.time = (SELECT MAX(time) FROM table1 AS t1 WHERE t1.date = table1.date)
I don't have MySQL but here is the general idea you can use. I don't have enough points to write a comment so I am responding as a reply. Essentially make a subquery/inline view for each table to select max of a column, then join those subqueries/inline views together.
Here is Oracle syntax. You can convert it to ANSI syntax.
select table1.column1, table2.column2,table3.column3
from
(select id1, max(column1) as column1 from table1 group by id1) as table1
(select id2, max(column2) as column2 from table2 group by id2) as table2
(select id3, max(column3) as column3 from table3 group by id3) as table3
where
table1.id1 = table2.id2
and table1.id1 = table3.id3
;
Related
Table 1:
user score
------------
A 1
B 2
Table 2:
user comment time
----------------------------
A good <timestamp 1>
A bad <timestamp 2>
B average <timestamp 3>
I want to join these two tables such that I get the below:
user score comment
-------------------------
A 1 good
B 2 average
As you can see I'll need to join the second table's comment based on the timestamp (the most recent timestamp). I tried
SELECT st.user as user,st.score,
case when v.comment is null then 'NA' else v.comment end as comment
FROM tale1
left JOIN (select distinct user,comment,max(time) from table2) v ON st.user=v.user
but this doesnt work.
You can join with a correlated subquery that filters on the latest timestamp:
select
t1.*,
t2.comment
from table1 t1
left join table2 t2
on t2.user = t1.user
and t2.time = (
select max(t22.time)
from table2 t22
where t21.user = t1.user
)
Side note: I am unsure that you do need a left join here (your sample data does not demonstrate that).
You only want one column from table2 so I recommend a correlated subquery:
select t1.*,
(select t2.comment
from table2 t2
where t2.user = t1.user
order by t2.time desc
limit 1
) as comment
from table1 t1;
This query will make optimal use of an index on table2(user, time desc, comment) -- alas, though, I think the desc is ignored in MySQL.
I have the following tables:
table1
id
name
number
status
table2
id
table1_id
transaction_no
transaction_date
I want to return a list of table1.name, table1.num, table2.transaction_no where the table1.status = "Active" and the lastest table2.transaction_date is older than 4 months.
I keep trying something like this but the syntax fails in various places.
SELECT tab1.name, tab1.num, tab2.transaction_no
FROM table1 AS tab1
INNER JOIN table2 AS tab2 ON tab1.id = tab2.table1_id
WHERE tab1.status = "Active"
AND
(SELECT MAX(tab2.transaction_date) FROM tab2
GROUP BY tab1.name) <= (date 4 months ago)
I know this is not right but my brain is struggling to wrap around the idea, or I making it more complicated that it is. Any suggestions or guidance would be greatly appreciated.
That GROUP BY tab1.name doesn't make sense in your subquery. tab1 isn't in context in your subquery (nor istab2 for that matter). Instead though you could do a correlated subquery:
AND (SELECT MAX(t2.transaction_date) FROM table2 t2 WHERE t2.table1_id = tab1.id) <= (date 4 months ago)
Now that subquery can stand on it's own, and it is properly correlated to the main query by way of it's WHERE clause.
If you only want the latest t2 record (and it has to be more than 4 months ago) then a subquery in your FROM clause would work:
SELECT tab1.name, tab1.num, tab2.transaction_no
FROM table1 AS tab1
INNER JOIN (
SELECT transaction_no, table1_id
FROM table2 t2
WHERE transaction_date = (SELECT max(transaction_date) FROM table2 WHERE table1_id = t2.table1_id)
) AS tab2
ON tab1.id = tab2.table1_id
WHERE tab1.status = "Active";
Here we are still using a correlated subquery to grab the record from table2 that has the greatest transaction_date for each table1_id. Then we are joining that one record per table1_id back to table1.id.
the sql as follows come from mysql document. it is:
SELECT * FROM t1 AS t
WHERE 2 = (SELECT COUNT(*) FROM t1 WHERE t1.id = t.id);
The document say It finds all rows in table t1 containing a value that occurs twice in a given column , and doesnot explain the sql.
t1 and t is the same table, so the
count(*) in subquery == select count(*) from t
, isn't it?
count(*) in subquery == select count(*) from t
is wrong. because in mysql you can't use it like that. so you have to run it like that to get result of same id having two rows.
if you want to get count of same occurrence,
SELECT id, name, count(*) AS all_count FROM t1 GROUP BY id HAVING all_count > 1 ORDER BY all_count DESC
And also you can get values as your query like this as well,
select * from t1 where id in ( select id from t1 group by id having count(*) > 1 )
The query contains a correlated subquery in WHERE clause:
SELECT COUNT(*) FROM t1 WHERE t1.id = t.id
It is called correlated because it is related to the main query via t.id. So, this subquery counts the number of records having an id value that is equal to the current id value of the record returned by the main query.
Thus, predicate
(SELECT COUNT(*) FROM t1 WHERE t1.id = t.id) = 2
evaluates to true for any row with an id value that occurs twice in the table.
SELECT * FROM t1 AS t
WHERE 2 = (SELECT COUNT(*) FROM t1 WHERE t1.id = t.id);
This query goes through each record in t1 and then in the subquery looks into t1 again to see if in this case id is found 2 times (and only 2 times). You can do the same for any other column in t1 (or any table for that matter).
When you would like to see all values that are multiple times in the table, change WHERE 2 = by WHERE 1 <. This will also give you the values that are 3 times, 4 times, etc. in the table.
{
SELECT id,count( * )
FROM
MyTable
group by id
having count( * )>1
}
with this code, you can see the rows which repet more than one,
and you can change this query by yourself
How about using GROUP BY and HAVING:
SELECT id, count(1) as Total FROM MyTable AS t1
GROUP BY t1.id
HAVING Total = 2
I have 3 tables and want to join all in one query to show latest 10 entries by datetime.
t1: id, username
t2: id, id_t1, med_id, ga_id, au_id, re_id, text, datetime
t3: id, id_t1, pro_id, au_id, re_id, text, datetime
First I saw it would be easy with simple left join and where id, but i got double results. Then i tried inner and outer join, also group by, but the result was bad.
So my question is how can i join all without double results of the last 10 of t2 and t3?
Hard to tell what exactly you are trying to acheive, but here is a clue how it could be complemented.
SELECT TOP 10 DISTINCT T1.*
FROM T1
INNER JOIN T2 ON T1.id = T2.id_t1
INNER JOIN T3 ON T1.id = T3.id_t1
ORDER BY (CASE WHEN T2.[DateTime] > T3.[DateTime] THEN
T2.[DateTime]
ELSE
T3.[DateTime]
END) DESC
If you need to select field from T2 and T3, GROUP BY on all T1 field with aggregate on field from t2 and t3 is an option. Otherwise, linked-subquery is the way to go.
As sgeddes commented already, it's hard to know what you need, without seeing some example data from your tables. It would really help to know what the relationship between the three tables is.
One question I have, in particular, is: how are t2 and t3 related, if at all? It looks like they might not be, as each of them has its own datetime column.
Perhaps the following could do the job, but we need some more info to know for sure:
(SELECT DISTINCT t1.*, t2.id, t2.au_id, t2.re_id, t2.text, t2.`datetime`, t2.med_id, t2.ga_id, NULL AS pro_id
FROM t1
INNER JOIN t2 ON t1.id = t2.id_t1)
UNION
(SELECT DISTINCT t1.*, t3.id, t3.au_id, t3.re_id, t3.text, t3.`datetime`, NULL AS med_id, NULL AS ga_id, t3.pro_id
FROM t1
INNER JOIN t3 ON t1.id = t3.id_t1)
ORDER BY datetime DESC
LIMIT 10
The following selects the username and the datetime for the last ten posts.
SELECT username, last_ten.`datetime` AS lastpost
FROM t1
INNER JOIN (
SELECT 't2' AS tab, id, `datetime`, t2.id_t1
FROM t2
UNION ALL
SELECT 't3' AS tab, id, `datetime`, t3.id_t1
FROM t3
ORDER BY datetime DESC
LIMIT 10
) AS last_ten ON t1.id = last_ten.id_t1
I have the following two tables:
Table1 {T1ID, Name}
Table2 {T2ID, T1ID, Date, Value}
Date is of type DATE.
and I am looking for a SQL query to fetch only the latest value (by Date) for each T1ID for which the Name matches a specific string.
SELECT`Table2`.`T1ID`,
`Table2`.`Value`,
`Table2`.`Date`,
`Table1`.`Name`,
FROM `Table1`
INNER JOIN `Table2` ON `Table2`.`T1ID` = `Table1`.`T1ID`
WHERE `Table1`.`Name` LIKE 'Smith'
but this returns the value for several dates for the same T1ID.
How do I get only the latest value by Date?
Edit:
I am using MySQL 5.5.8
If I've understodd the question correctly:
Assuming MySQL:
SELECT`Table2`.`T1ID`,
`Table2`.`Value`,
`Table2`.`Date`,
`Table1`.`Name`
FROM `Table1`
INNER JOIN `Table2` ON `Table2`.`T1ID` = `Table1`.`ID`,
(SELECT T1ID, MAX(Date) AS 'Date' FROM Table2 GROUP BY T1ID) Table3
WHERE
`Table3`.`T1ID` = `Table2`.`T1ID`
AND
`Table3`.`Date` = `Table2`.`Date`
AND
`Table1`.`Name` LIKE 'Smith'
EDIT: Updated the code to bring back the correct result set. Removed MSSQL answer as it wasn't relevant
You have two options.
select t1.t1id, max(t1.Name) Name, max(t2.date) Date,
(select Value from table2 t22
where t22.date = max(t2.date) and t22.t1id = t2.t1id) Value
from table1 t1 left join table2 t2 on t1.t1id = t2.t1id
where Name like '%Smith%'
group by t2.t1id order by 2
OR
select mx.t1id, mx.Name, mx.Date, t2.Value
from
(
select t1.t1id, max(t1.Name) Name, max(t2.date) Date
from table1 t1 left join table2 t2 on t1.t1id = t2.t1id
where Name like '%Smith%'
group by t2.t1id
) mx left join table2 t2 on (t2.t1id = mx.t1id and t2.date = mx.date)
order by 2
Both will produce the same result. The first one takes less code but you might have performance issues with a huge set of data. The second one takes a little more code, but it is also a little more optimized. Notes on the JOIN option:
If you go LEFT JOIN (as the example shows), items in Table1 with no correspondent records on Table2 will be displayed in the result, but the values in columns Date and Value will be NULL
If you go INNER JOIN, items in Table1 with no correspondent records on Table2 will not be displayed.
EDIT
I missed one of the requirements, which was the Name matching a specific string. The code is now updated. The '%' acts like a wildcard, so it will match names like 'Will Smith' and 'Wail Smithers'. If you want a exact match, remove the wildcards ('%').
Add this to your SQL:
ORDER BY 'Date' DESC LIMIT 1