I'm writing simple SQL Statement where I need to found my boss's boss. For example if there is three ranks in the column like (lil boss,boss and big boss) and I input lil boss id it need to return the the big boss id. I think that this query must be write white case or decode statements but i have struggles with that. In this code everything would run fine except if I input lil boss ID.Can I use nested decode or case statements? I think that UNION statement would be solution also .
If my table has three column:
id
status
boss_id
1
big boss
null
2
big boss
null
3
lil boss
4
4
boss
2
If I input 3 it have to return 2
select decode(status,'big boss', id,
'boss',boss_id,
'lil boss',boss_id)
from bosses
where id=123113;
I need to found my boss's boss
Use a hierarchical query:
SELECT CONNECT_BY_ROOT id AS root_id,
CONNECT_BY_ROOT status AS root_status,
id,
status
FROM bosses
WHERE LEVEL = 3
OR (LEVEL < 3 AND CONNECT_BY_ISLEAF = 1)
START WITH id = 2
CONNECT BY PRIOR boss_id = id;
Which, for the sample data:
CREATE TABLE bosses (id, status, boss_id) AS
SELECT 1, 'big boss', null FROM DUAL UNION ALL
SELECT 2, 'big boss', null FROM DUAL UNION ALL
SELECT 3, 'lil boss', 4 FROM DUAL UNION ALL
SELECT 4, 'boss', 2 FROM DUAL;
Outputs:
ROOT_ID
ROOT_STATUS
ID
STATUS
3
lil boss
2
big boss
and if you START WITH id = 2:
SELECT CONNECT_BY_ROOT id AS root_id,
CONNECT_BY_ROOT status AS root_status,
id,
status
FROM bosses
WHERE LEVEL = 3
OR (LEVEL < 3 AND CONNECT_BY_ISLEAF = 1)
START WITH id = 2
CONNECT BY PRIOR boss_id = id;
Then it outputs:
ROOT_ID
ROOT_STATUS
ID
STATUS
2
big boss
2
big boss
fiddle
I was able to come to a solution to this problem. For this purpose I used hierarchical queries and the solution of #MT0. Here is the code that not need to use level. I think it is the best and simpliest solution to the problem. Thanks for helping me!
select id as bossid,
status as boss_status
from bosses b
where b.status='big boss'
start with id ='4'
connect by prior boss_id = id;
Related
I've a data base with two tables.
Table Players Table Wins
ID Name ID Player_won
1 Mick 1 2
2 Frank 2 1
3 Sarah 3 4
4 Eva 4 5
5 Joe 5 1
I need a SQL query which show "The players who have not won any game".
I tried but I don't know even how to begin.
Thank you
You need all the rows from players that don't have corresponding rows in wins. For this you need a left join, filtering for rows that don't join:
select
p.id,
p.name
from Players p
left join Wins w on w.Player_won = p.id
where w.Player_won is null
You can also use not in:
select
id,
name
from Players
where id not in (select Player_won from Wins)
How about the MINUS set operator?
Sample data:
SQL> with players (id, name) as
2 (select 1, 'Mick' from dual union all
3 select 2, 'Ffrank' from dual union all
4 select 3, 'Sarah' from dual union all
5 select 4, 'Eva' from dual union all
6 select 5, 'Joe' from dual
7 ),
8 wins (id, player_won) as
9 (select 1, 2 from dual union all
10 select 2, 1 from dual union all
11 select 3, 4 from dual union all
12 select 4, 5 from dual union all
13 select 5, 1 from dual
14 )
Query begins here:
15 select id from players
16 minus
17 select player_won from wins;
ID
----------
3
SQL>
So, yes ... player 3 didn't win any game so far.
I think you should provide your attempts next time, but here you go:
select p.name
from players p
where not exists (select * from wins w where p.id = w.player_won);
MINUS is not the best option here because of not using indexes and instead performing a full-scan of both tables.
I've a data base with two tables.
You don't show the names or any definition of the tables, leaving me to make an educated guess about their structure.
I tried but I don't know even how to begin.
What exactly did you try? Possibly what you are missing here is the concept of a LEFT OUTER JOIN.
Assuming the tables are named player_table and wins_table, and have column names exactly as you showed, and that the player_won column is intended to express the number of games won by the player of that row's ID, and without knowing whether or not wins_table will have rows for players with zero wins… this should cover it:
select Name
from players_table pt
left join wins_table wt on (pt.ID = wt.ID)
-- Either this player is explicitly specified to have Player_won=0
-- or there is no row for this player ID in the wins table
-- (but excluding the possibility of an explicit NULL value, since its meaning would be unclear)
where Player_won = 0 or wt.ID is null;
As you can see from the variety of answers you've gotten, there are many ways to accomplish this.
One additional way to do this is to use COUNT in a correlated subquery, as in:
SELECT *
FROM PLAYERS p
WHERE 0 = (SELECT COUNT(*)
FROM WINS w
WHERE w.PLAYER_WON = p.ID)
db<>fiddle here
SELECT *
FROM Players p
INNER JOIN Wins w
ON p.ID = w.ID
WHERE w.players_won = 0
I have not done SQL in awhile but I think this might be right if you are looking for players with 0 wins
I have a table (in SQL Server) that stores records as shown below. The purpose for Old_Id is for change tracking.
Meaning that when I want to update a record, the original record has to be unchanged, but a new record has to be inserted with a new Id and with updated values, and with the modified record's Id in Old_Id column
Id Name Old_Id
---------------------
1 Paul null
2 Paul 1
3 Jim null
4 Paul 2
5 Tim null
My question is:
When I search for id = 1 or 2 or 4, I want to select all related records.
In this case I want see records the following ids: 1, 2, 4
How can it be written in a stored procedure?
Even if it's bad practice to go with this, I can't change this logic because its legacy database and it's quite a large database.
Can anyone help with this?
you can do that with Recursive Common Table Expressions (CTE)
WITH cte_history AS (
SELECT
h.id,
h.name,
h.old_id
FROM
history h
WHERE old_id IS NULL
and id in (1,2,4)
UNION ALL
SELECT
e.id,
e.name,
e.old_id
FROM
history e
INNER JOIN cte_history o
ON o.id = e.old_id
)
SELECT * FROM cte_history;
EDIT: added third requirement after playing with solution from Tim Biegeleisen
EDIT2: modified Robbie's DOB to be before his parent's marriage date
I am trying to create a query that will look at two tables and determine the difference in dates based on a percentage. I know, super confusing... Let me try and explain using the tables below:
Bob and Mary are married on 2010-01-01 and expect 4 kids (Parent table)
I want to know how many years it took until they met 50% of their expected kids (i.e. 2/4 kids). Using the Child table to see the DOB of their 4 kids, we know that Frankie is the second child which meets our 50% threshold so we use Frankie's DOB and subtract it from Frankie's parent's marriage date and end up with 3 years!
If the goal isn't reached then display no value e.g. Mick and Jo only had 1 child so far so they haven't yet reached their goal
Hoping this is doable using BigQuery standard SQL.
Parent table
id married_couple married_at expected_kids
--------------------------------------
1 Bob and Mary 2010-01-01 4
2 Mick and Jo 2010-01-01 4
Child table
id child_name parent_id date_of_birth
--------------------------------------
1 Eddie 1 2012-01-01
2 Frankie 1 2013-01-01
3 Robbie 1 2005-01-01
4 Duncan 1 2015-01-01
5 Rick 2 2014-01-01
Expected SQL result
parent_id half_goal_reached(years)
--------------------------------------
1 3
2
Below both soluthions for BigQuery Standard SQL
First one is more in classic sql way, the second one is more of BigQuery style (I think)
First Solution: with analytics function
#standardSQL
SELECT
parent_id,
IF(
MAX(pos) = MAX(CAST(expected_kids / 2 AS INT64)),
MAX(DATE_DIFF(date_of_birth, married_at, YEAR)),
NULL
) AS half_goal_reached
FROM (
SELECT c.parent_id, c.date_of_birth, expected_kids, married_at,
ROW_NUMBER() OVER(PARTITION BY c.parent_id ORDER BY c.date_of_birth) AS pos
FROM `child` AS c
JOIN `parent` AS p
ON c.parent_id = p.id
)
WHERE pos <= CAST(expected_kids / 2 AS INT64)
GROUP BY parent_id
Second Solution: with use of ARRAY
#standardSQL
SELECT
parent_id,
DATE_DIFF(dates[SAFE_ORDINAL(CAST(expected_kids / 2 AS INT64))], married_at, YEAR) AS half_goal_reached
FROM (
SELECT
parent_id,
ARRAY_AGG(date_of_birth ORDER BY date_of_birth) AS dates,
MAX(expected_kids) AS expected_kids,
MAX(married_at) AS married_at
FROM `child` AS c
JOIN `parent` AS p
ON c.parent_id = p.id
GROUP BY parent_id
)
Dummy Data
You can test / play with both solutions using below dummy data
#standardSQL
WITH `parent` AS (
SELECT 1 id, 'Bob and Mary' married_couple, DATE '2010-01-01' married_at, 4 expected_kids UNION ALL
SELECT 2, 'Mick and Jo', DATE '2010-01-01', 4
),
`child` AS (
SELECT 1 id, 'Eddie' child_name, 1 parent_id, DATE '2012-01-01' date_of_birth UNION ALL
SELECT 2, 'Frankie', 1, DATE '2013-01-01' UNION ALL
SELECT 3, 'Robbie', 1, DATE '2014-01-01' UNION ALL
SELECT 4, 'Duncan', 1, DATE '2015-01-01' UNION ALL
SELECT 5, 'Rick', 2, DATE '2014-01-01'
)
Try the following query, whose logic is too verbose to explain it well. I join the parent and child tables, bringing into line the parent id, number of years elapsed since marriage, running number of children, and expected number of children. With this information in hand, we can easily find the first row whose running number of children matches or exceeds half of the expected number.
SELECT parent_id, num_years AS half_goal_reached
FROM
(
SELECT parent_id, num_years, cnt, expected_kids,
ROW_NUMBER() OVER (PARTITION BY id ORDER BY num_years) rn
FROM
(
SELECT
t2.parent_id,
YEAR(t2.date_of_birth) - YEAR(t1.married_at) AS num_years,
(SELECT COUNT(*) FROM child c
WHERE c.parent_id = t2.parent_id AND
c.date_of_birth <= t2.date_of_birth) AS cnt,
t1.expected_kids
FROM parent t1
INNER JOIN child t2
ON t1.id = t2.parent_id
) t
WHERE
cnt >= expected_kids / 2
) t
WHERE t.rn = 1;
Note that there may be issues with how I computed the yearly differences, or how I compute the threshhold for half the number of expected children. Also, if we were using a recent enterprise database we could have used an analytic function to get the running number of children instead of a correlated subquery, but I was unsure if Big Query would support that, so I used the latter.
I have a table with a structure like (id, parent_id) in Oracle11g.
id parent_id
---------------
1 (null)
2 (null)
3 1
4 3
5 3
6 2
7 2
I'd like to query it to get all the lines that are hierarchically linked to each of these id, so the results should be :
root_id id parent_id
------------------------
1 3 1
1 4 3
1 5 3
2 6 2
2 7 2
3 4 3
3 5 3
I've been struggling with the connect by and start with for quite some time now, and all i can get is a fraction of the results i want with queries like :
select connect_by_root(id) root_id, id, parent_id from my-table
start with id=1
connect by prior id = parent_id
I'd like to not use any for loop to get my complete results.
Any Idea ?
Best regards,
Jérôme Lefrère
PS : edited after first answer, noticing me i had forgotten some of the results i want...
The query you posted is missing the from clause and left an underscore out of connect_by_root, but I'll assume those aren't actually the source of your problem.
The following query gives you the result you're looking for:
select * from (
select connect_by_root(id) root_id, id, parent_id
from test1
start with parent_id is null
connect by prior id = parent_id)
where root_id <> id
The central problem is that you were specifying a specific value to start from, rather that specifying a way to identify the root rows. Changing id = 1 to parent_id is null allows the entire contents of the table to be returned.
I also added the outer query to filter the root rows out of the result set, which wasn't mentioned in your question, but was shown in your desired result.
SQL Fiddle Example
Comment Response:
In the version provided, you do get descendants of id = 3, but not in such a way that 3 is the root. This is because we're starting at the absolute root. Resolving this is easy, just omit the start with clause:
SELECT *
FROM
(SELECT connect_by_root(id) root_id,
id,
parent_id
FROM test1
CONNECT BY
PRIOR id = parent_id)
WHERE root_id <> id
SQL Fiddle Example
try this:
select connect_by_root(id) root_id, id, parent_id
from your_table
start with parent_id is null
connect by prior id = parent_id
It will give you the exact result you want:
select connect_by_root(id) as root, id, parent_id
from test1
connect by prior id=parent_id
start with parent_id is not null;
I have a table that shows the relationships between people a bit like this.
id linked_id
1 2
1 3
3 4
4 1
There is no apparent order to the table or the relationships.
I'm trying to find a way to list all the ids that have any kind of link to a given id. So for examples from the table above:
id = 1 would return 1, 2, 3 and 4.
id = 2 would also return 1, 2, 3 and 4
It's an oracle database, and the query would have to be in plain SQL. Thanks for your help, this has been driving me nuts.
You could use something like this:
SELECT linked_id
FROM DATA
START WITH ID = :1
CONNECT BY NOCYCLE PRIOR ID = linked_id
OR ID = PRIOR linked_id
UNION
SELECT ID
FROM DATA
START WITH linked_id = :1
CONNECT BY NOCYCLE PRIOR ID = linked_id
OR ID = PRIOR linked_id
UNION
SELECT :1 FROM dual