I´m getting a strange result from a SQLite query. The query is the next one:
SELECT rule FROM rules
WHERE idRule = (SELECT idRuleForeign FROM rulesXfilter
WHERE idFilterForeign = (SELECT idFilter FROM filters
WHERE name = 'Filter1'));
Now, let´s suppose that I have the following tables with a few rows on it.
filters rules rulesXfilter
idFilter name idRule rule idRuleForeign idFilterForeign
1 Filter1 1 Rule1 1 1
2 Filter2 2 Rule2 2 1
3 Rule3 3 1
2 2
What I get is {Rule1}, although I think I should get {Rule1, Rule2, Rule3}
What am I doing wrong?
Select idRuleForeign... returns multiple results, yes ({1, 2, 3}). However, you then say "give me the rule where idRule = {SET}", and sql doesnt like this. I believe what is happening is that it is instead taking the first result only and giving you that.
The solution is to use joins. Inner selects like that, while work most of the time, can REALLY slow down your query. If I got my syntax correct, the following should do what you need:
SELECT r.rule FROM rules r
JOIN rulesXfilter rf ON r.idRule = rf.idRuleForeign
JOIN filters f ON f.idFilter = rf.idFilterForeign
WHERE f.name = 'Filter1'
Related
Here's a sample of what I'm trying to do:
select
t1.Field1
t1.Field2
from Table1 t1
inner join Table2 t2 on t2.Field1 = t1.Field1
where
t1.Field3 like '123-%'
and t1.CreateDate >= '01/01/2021'
having
Count(t2.Field4 = 419) >= 1
2 tables
Table 1 has unique records with an ID (Field 1)
Table 2 has multiple records, with ID Field 1 as well. Table2 may have 10, 20, etc records for Field1. I'm wanting to pull Table1 records where Table2 as at least 1 occurrence of Field4 = 419. Table2 may not have any Field4=419, it may have 1, or it may have 2 or more.
Pretty straight forward I think, but unfortunately I'm new to SQL writing which I why I'm posting for help as I've tried several ways to get this to work without any luck.
Normally you use having when you have a group by in your query.
There will be multiple ways of writing what you want, but one way that I think is easy to understand is selecting from Table1 and doing the count of Table2 in a subquery of the where clause. Depending on the size of your tables and the indexing, you might want to explore other options, but I think this is at least a good starting point that does what you want.
select
t1.Field1
t1.Field2
from Table1 t1
where
t1.Field3 like '123-%'
and t1.CreateDate >= '01/01/2021'
and (SELECT count(*) FROM Table2 t2 WHERE t2.Field1 = t1.Field1 AND t2.Field4 = 419) >= 1
I have a string like this ('car, bus, train')
I want to convert it to be used in an in-clause. Basically I want to convert it to
('car','bus','train'). Please how do I do this in Teradata
I don't know how you are getting data like that, but if you have no control over that, you can use STRTOK_SPLIT_TO_TABLE.
select t.* from table (strtok_split_to_table(1,'car, bus, train',',')
returns (outkey integer,tokennum integer,resultstring varchar(25))) as t
Run by itself, that gives you:
outkey tokennum resultstring
1 1 car
1 2 bus
1 3 train
You can use that as a derived table and join it to the table you want to filter by. Something like:
select
<your table>.*
from
<your table>
inner join (select t.* from table (strtok_split_to_table(1,'car, bus, train',',')
returns (outkey integer,tokennum integer,resultstring varchar(25))) as t) dt
on yourtable.yourcolumn = dt.resultstring
here is the another way of spliting the input for n number of commas and use IN clause.
SELECT regexp_substr('car,bus,train','[^,]+',1,day_of_calendar) fields
FROM sys_calendar.calendar
WHERE day_of_calendar <= (CHAR('car,bus,train') - CHAR(oreplace('car,bus,train',',','')))+1;
Output of the Query
fields
~~~~~~~~
bus
car
train
Here is the systax to use in where clause
SELECT * FROM <your table>
WHERE yourtable.requiredColumn in
(
SELECT regexp_substr('car,bus,train','[^,]+',1,day_of_calendar) fields
FROM sys_calendar.calendar
WHERE
day_of_calendar <= (CHAR('car,bus,train') - CHAR(oreplace('car,bus,train',',','')))+1
);
Basically what we are doing here is splitting the string for each comma and below function is calculating number of commas in the string
(CHAR('car,bus,train') - CHAR(oreplace('car,bus,train',',','')))+1
I am trying to write a query that will check to see if values in one table have any corresponding entries in other tables. I have the following which works but is there a faster way? Maybe using exists() function?
For clarification, this will be in sqlite. Also, I need values for each row in Manufacturer and whether or not it has entries in any of the other tables.
select tM.val, min(t1.val) as MakesCars, min(t2.val) as MakesTrucks,
min(t3.val) as MakesVans from tableManufactures tM
left join tableCars t1 on tM.id = t1.Manid
left join tableTrucks t2 on tM.id = t2.Manid
left join tableVans t3 on tM.id = t3.Manid
group by tM.val
order by tM.val
Results would look something like this:
Manufacturer MakesCars MakesTrucks MakesVans
Ford 85 15 20
Chevy 72 12 NULL
Mazda 42 NULL NULL
So any value would indicate that they do make that and a null would indicate that they don't.
For the joins, the database has to look up all matching records, most of which are then dropped because of the min().
Using EXISTS indeed is likely to be more efficient:
SELECT val,
EXISTS (SELECT 1
FROM tableCars
WHERE Manid = tM.id) AS MakesCars,
EXISTS (SELECT 1
FROM tableTrucks
WHERE Manid = tM.id) AS MakesTrucks,
EXISTS (SELECT 1
FROM tableVans
WHERE Manid = tM.id) AS MakesVans
FROM tableManufactures AS tM
ORDER BY val
I don't know if I'm being dumb here but I can't seem to find an efficient way to do this. I wrote a very long and inefficient query that does what I need, but what I WANT is a more efficient way.
I have 2 result sets that displays an ID (a PK which is generic/from the same source in both sets) and a FLAG (A - approve and V - Validate).
Result Set 1
ID FLAG
1 V
2 V
3 V
4 V
5 V
6 V
Result Set 2
ID FLAG
2 A
5 A
7 A
8 A
I want to "merge" these two sets to give me this output:
ID FLAG
1 V
2 (V/A)
3 V
4 V
5 (V/A)
6 V
7 A
8 A
Neither of the 2 result sets will at any time have all the ID's to make a simple left join with a case statement on the other result set an easy solution.
I'm currently doing a union between the two sets to get ALL the ID's. Thereafter I left join the 2 result sets to get the required '(V/A)' by use of a case statement.
There must be a more efficient way but I just can't seem to figure it out now as I'm running low on amps... I need a holiday... :-/
Thanks in advance!
Use a FULL OUTER JOIN:
SELECT ID,
CASE
WHEN t1.FLAG IS NULL THEN t2.FLAG
WHEN t2.FLAG IS NULL THEN t1.FLAG
ELSE '(' || t1.FLAG || '/' || t2.FLAG || ')'
END AS MERGED_FLAG
FROM TABLE1 t1
FULL OUTER JOIN TABLE2 t2
USING (ID)
ORDER BY ID
See this SQLFiddle.
Share and enjoy.
I think that you can use xmlagg. Here an exemple :
SELECT deptno,
SUBSTR (REPLACE (REPLACE (XMLAGG (XMLELEMENT ("x", ename)
ORDER BY ename),'</x>'),'<x>','|'),2) as concated_list
FROM emp
GROUP BY deptno
ORDER BY deptno;
Bye
Here is my example table:
column_example
10
20
25
50
Here is what I would like:
column_example2
10
5
25
I'm sure this is a simple question, but I haven't found the answer in the SQLite Syntax web page or via Google.
EDIT: To clarify, the code would likely return the outputs for:
20-10
25-20
50-25
This solution might be slow, but I had to consider the potential gaps between succeeding rowids:
http://sqlfiddle.com/#!5/daeed/1
SELECT
(SELECT x
FROM t AS t3
WHERE t3.rowid =
(SELECT MIN(tt.rowid)
FROM t AS tt
WHERE tt.rowid > t.rowid
)
)
- x
FROM t
WHERE diff IS NOT NULL
If it is guaranteed to not have any gaps between rowids, then you can use this simpler query:
http://sqlfiddle.com/#!5/1f906/3
SELECT t_next.x - t.x
FROM t
INNER JOIN t AS t_next
ON t_next.rowid = t.rowid + 1