I have 2 tables in Mysql which looks as follows
Table 1
ID YEARMONTH
------------------
1 201210
2 201211
3 201212
Table2
ID YEARMONTH GRADE DESIG
--------------------------------
1 201210 G1 NULL
2 201210 G1 D2
3 201212 G1 D1
I am trying to set a new field (named FLAG) in table1 which will be Y if rows exist for t1.YEARMONTH in T2 else N
I want the following Result in T1
ID YEARMONTH FLAG
---------------------
1 201210 Y
2 201211 N
3 201212 Y
I have tried the following Query
SELECT
T1.ID,
T1.YEARMONTH,
CASE COUNT(T2.ID)
WHEN (SELECT
COUNT(T2.ID)
FROM TABLE2 T2)
> 0 THEN 'Y'
ELSE 'N'
END AS flag
FROM TABLE1 T1,
table2 T2;
But it produces the following output
ID YEARMONTH FLAG
---------------------------
1 201210 N
I don't know where my mistake lies. Any help would be appreciated.
Try using the below query:
SELECT
T1.ID, T1.YEARMONTH,
(CASE
WHEN COUNT(T2.ID) > 0 THEN 'Y'
ELSE 'N'
END) AS FLAG
FROM TABLE1 T1
LEFT JOIN TABLE2 T2
ON T1.YEARMONTH = T2.YEARMONTH
GROUP BY T1.ID, T1.YEARMONTH
You can see the required output here http://sqlfiddle.com/#!9/162855/12
TRY THIS: Using CASE with LEFT JOIN you can check the existence of t1.yearmonth in t2.yearmonth and generate the flag column accordingly
SELECT DISTINCT t1.id,
t1.yearmonth,
(CASE WHEN t2.yearmonth IS NOT NULL THEN 'y' ELSE 'n' END) flag
FROM table1 t1
LEFT JOIN table2 t2 ON t1.yearmonth = t2.yearmonth
Related
Suppose, I have a table t1 looking like
id
value1
value2
wk_id
1
2
0
1
1
1
1
2
1
3
0
3
2
2
1
2
2
2
0
3
3
1
0
2
3
2
0
4
3
3
0
5
And I want to sum up the value1 till non-zero value appears on the value2 for first time.
End product must look like this:
id
value1
1
2
2
0
3
6
How to perform this in SQL?
If your MySQL version support window function you can try to use SUM window function with condition aggregate function be a flag to represent your logic (till non-zero value appears on the value2 for first time)
Then do condition aggregate function again.
Query #1
SELECT id,
SUM(CASE WHEN flag = 0 THEN value1 ELSE 0 END) value1
FROM (
SELECT *,
SUM(CASE WHEN value2 = 1 THEN -1 ELSE 0 END) OVER(PARTITION BY ID ORDER BY wk_id) flag
FROM T
) t1
GROUP BY id;
id
value1
1
2
2
0
3
6
View on DB Fiddle
WITH cte AS (
SELECT *,
CASE WHEN SUM(value2) OVER (partition by id ORDER BY wk_id) = 0
THEN SUM(value1) OVER (partition by id ORDER BY wk_id)
ELSE 0
END sum_value1
FROM test
ORDER BY id, wk_id
)
SELECT id, MAX(sum_value1) sum_value1
FROM cte
GROUP BY id;
https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=0fcdca008e4a821f952de4d608434bcf
One option is a NOT EXISTS clause, looking for the stop row (the first row with value2 = 1).
select id, sum(value1)
from mytable
where not exists
(
select null
from mytable stoprow
where stoprow.id = mytable.id
and stoprow.wk_id <= mytable.wk_id
and stoprow.value2 = 1
)
group by id
order by id;
Aggregating on a calculated rolling total of value2 can also be done via a self-join.
select id
, sum(if(roll_tot_value2=0,value1,0)) as total
from
(
select t1a.id, t1a.wk_id, t1a.value1
, sum(t1b.value2) as roll_tot_value2
from t1 as t1a
join t1 as t1b
on t1b.id = t1a.id
and t1b.wk_id <= t1a.wk_id
group by t1a.id, t1a.wk_id, t1a.value1
) q
group by id;
id
total
1
2
2
0
3
6
Test on db<>fiddle here
You can use a subquery:
select t.id, coalesce(
(select sum(t2.value1) from t1 t2 where t2.value2 = 0 and t2.id = t.id
and (not exists (select 1 from t1 t3 where t3.value2 = 1 and t3.id = t.id)
or t2.wk_id < (select min(t4.wk_id) from t1 t4 where t4.id = t.id and t4.value2 = 1))), 0)
from t1 t group by t.id
I have a correlated subquery that is validated based on the column value. Even though I read through the sequelize docs and examples on GitHub, I did not really get any working solutions.
Query I am trying to execute
select count(*) from table1 t1
where case when deciding_col=1 then t1.id in
(select distinct t2.id from table2 t2 where t2.id=t1.id and t2.second_condition=132)
else 1=1 end;
Any references or suggestions are appreciated.
Update:
The goal is to fetch all records from table1, but if deciding_col value is true for a record, then I need to check if that particular record exist in table2.
Example:
Table1 Data:
id | name | deciding_col
1 abcd 1
2 edfg 0
3 xyz 0
Table2 Data:
id | second_condition
1 132
Output:
1.
select t1.* from table1 t1
where case when deciding_col=1 then t1.id in
(select distinct t2.id from table2 t2 where t2.id=t1.id and t2.second_condition=132)
else 1=1 end;
id | name | deciding_col
1 abcd 1
2 edfg 0
3 xyz 0
2.
select t1.* from table1 t1
where case when deciding_col=1 then t1.id in
(select distinct t2.id from table2 t2 where t2.id=t1.id and t2.second_condition=133)
else 1=1 end;
id | name | deciding_col
2 edfg 0
3 xyz 0
The following are my mysql tables
Table 1:
ID | commonID | Date | text | active
1 11 01.02 abc 1
2 11 02.02 123 1
3 11 03.02 xyz 0
Table 2:
ID | commonID | Date | value | active
1 11 01.02 abc 1
2 11 04.02 123 1
3 11 03.02 xyz 1
The Final result should display this:
| date | text | value
01.02 abc abc
02.02 123 (null)
03.02 (null) xyz
04.02 (null) 123
The Idea here is, to merge the two tables. All entries with a defined commonID like 11 in the example will be selected from both tables. then the tables will be united.
Conditions:
If there are matching dates in TABLE1 and TABLE2 they will be merged
If there is a solo date in TABLE1 or TABLE2, the value/text for the table with no date will become NULL
If there is a record in TABLE1 or TABLE2 that has active = FALSE, it will not be processed.
There can be matching and not matching dates in BOTH tables.
I want to use this for display chronologic events, if there is an event in both tables, there should be only one line for this.
What could be the Solution here?
Try this:
SELECT T1.date,
CASE WHEN T1.active = 1 THEN T1.text END as text,
CASE WHEN T2.active =1 THEN T2.value END as value
FROM Table1 T1 LEFT JOIN
Table2 T2 ON T1.date=T2.date
UNION
SELECT T2.date,
CASE WHEN T1.active = 1 THEN T1.text END as test,
CASE WHEN T2.active = 1 THEN T2.value END as value
FROM Table1 T1 RIGHT JOIN
Table2 T2 ON T1.date=T2.date
Result:
DATE TEXT VALUE
01.02 abc abc
02.02 123 (null)
03.02 (null) xyz
04.02 (null) 123
Sample SQL Fiddle.
Try this:
SELECT t1.date,t1.text,t2.value FROM table1 t1
LEFT JOIN table2 t2 ON t1.commonId = t2.commonId and t1.date = t2.date and t2.active = 1
where t1.active = 1
UNION
SELECT t2.date,t1.text,t2.value FROM table2 t2
LEFT JOIN table1 t1 ON t1.commonId = t2.commonId and t1.date = t2.date and t1.active = 1
where t2.active = 1
Sample http://sqlfiddle.com/#!2/d2c4d/2
Here's one way...
SELECT commonid
, date
, MAX(text) text
, MAX(value) value
FROM
( SELECT id
, commonid
, date
, text
, NULL value
, active
FROM table1
WHERE active <> 0
UNION
SELECT id
, commonid
, date
, NULL
, value
, active
FROM table2
WHERE active <> 0
) x
GROUP
BY commonid,date;
You can move the WHERE active <> 0 bit out of the UNIONs if you like, to just before the GROUP BY.
I've two tables named table1 and table2. table2 may have elements from table1. I'd like to show all the results from table2 with the price if available in table1 and with status 1. If no product matches in table1 and also status is 0, need to return price as 0.
table1
id pname item_code price status
1 product1 abcd 200 1
2 product2 pqrs 500 1
3 product3 wxyz 425 1
4 product5 mnop 100 0
and table2 as follows
id item_code
10 efgh
11 abcd
12 pqrs
13 mnop
I have tried following query
SELECT `t2`.`id`, `t2`.`item_code`, `t1`.`price`,`t1`.`pname`, COUNT(t2.item_code) AS sellers FROM (`table2` as t2) LEFT JOIN `table1` as t1 ON `t1`.`item_code` = `t2`.`item_code` WHERE `t1`.`status` = 1 GROUP BY `t2`.`item_code`
but it returns common values in table1 and table2 with status 1, but I need all records from table2 with price as 0 if nothing match in table1 or status 0 in table1.
Expected output
id item_code price
10 efgh 0
11 abcd 200
12 pqrs 500
13 mnop 0
Any help please.
Thanks,
Not sure about your current query which is having count and group by however you can do as below
select
t2.id,
t2.item_code,
case
when t1.status = 1 then t1.price
else 0
end as price
from table2 t2
left join table1 t1 on t1.item_code = t2.item_code
Now note that if table1 has multiple matching values from table2 in that case we may need grouping data.
Try below query:
SELECT `t2`.`id`, `t2`.`item_code`, `t1`.`price`,`t1`.`pname`, COUNT(t2.item_code) AS sellers FROM (`table2` as t2) LEFT JOIN (select * from table1 where status = 1)t1 ON `t1`.`item_code` = `t2`.`item_code` GROUP BY `t2`.`item_code`
Move the part of the WHERE clause that checks the left joined table to the ON clause
SELECT `t2`.`id`, `t2`.`item_code`, COALESCE(`t1`.`price`, 0),`t1`.`pname`, COUNT(t2.item_code) AS sellers
FROM (`table2` as t2)
LEFT JOIN `table1` as t1
ON `t1`.`item_code` = `t2`.`item_code`
AND`t1`.`status` = 1
GROUP BY `t2`.`item_code`
I have two tables:
table1:
id
--
1
2
3
table2: (left out primary index)
id2 | cond
----------
3 | 1
3 | 0
2 | 1
2 | 1
2 | 0
I would need to construct a query that implicitly calculates this intermediary table:
temp:
id | c1 | c2
------------
1 | 0 | 2
2 | 2 | 2
3 | 1 | 2
with c1 = countRows(id2 == id && cone == 1) and c2 == countRows(id2 = 2 && cond == 1).
and then selects SELECT id FROM temp ORDER BY ABS(c1 - c2)*RAND().
My current try is kind of like:
SELECT id, COUNT(t1.id2) AS c1, COUNT(t2.id2) AS c2
FROM table1 LEFT JOIN (table2 AS t1) ON id=t1.id2 LEFT JOIN (table2 AS t2) ON t2.id2=2
WHERE t1.cond=1 AND t2.cond=1
GROUP BY t1.id2
ORDER BY ABS(c1 - c2)*RAND()
LIMIT 1
Which has multiple problems:
It doesn't select rows with no entry in table2
It doesn't correctly count
There seems to be a problem with group columns (c1, c2) in the ORDER BY part 3.
Help would be appreciated.
Update:
table1 represents players for example
table2 would be rounds played, with cond indicating a win
c1 represents the rounds won by each player
c2 represents the rounds won by a reference player (player 2 in this case)
SELECT t1.id, SUM(IFNULL(t2.cond, 0) = 1) AS c1, (SELECT SUM(cond = 1) FROM table2 WHERE id2 = 2) AS c2
FROM table1 t1
LEFT JOIN table2 t2 ON t1.id = t2.id2
GROUP BY t1.id
ORDER BY ABS(SUM(IFNULL(t2.cond, 0) = 1) - c2) * RAND();
Let's see if the first part of your query is returning valid results..
SELECT
t1.id AS id
COUNT(t2.id2) AS c1
COUNT(CASE WHEN t3.id2 = 2 THEN t3.id2 ELSE NULL END) as c2
FROM
table1 AS t1
LEFT JOIN table2 as t2
ON t1.id = t2.id2 AND t2.cond = 1
LEFT JOIN table2 as t3
ON t3.id2 = 2 AND t3.cond = 1
GROUP BY
t2.id2,
t3.id2
Can you provide schema?