Here's my problem - Midstream in my data flow, we have some values in one column that we want to swap for other values based on a lookup table.
For example, if I had a rowset like this:
Key Value
1 A
2 B
3 A
4 C
5 D
6 B
... ...
If I had a lookup table in a SQL Server DB that looked like this:
Value1 Value2
C Y
D Z
Then I would want my package to swap only those values so the resulting data flow would look like this:
Key Value
1 A
2 B
3 A
4 Y
5 Z
6 B
... ...
What components would produce the simplest solution?
You could use a lookup component and then:
Set it up to Ignore Failure
Values that do not match will return null for the lookup value
Use a derived column expression to populate where the lookup succeeded
ISNULL(Value2) ? Value : Value2
Related
new to SQL.
I have the following set of data
A X Y Z
1 Wind 1 1
2 Wind 2 1
3 Hail 1 1
4 Flood 1 1
4 Rain 1 1
4 Fire 1 1
I would like to select all distinct 'A' fields where for all rows that contain A have flood and rain.
So in this example, the query would return only the number 4 since for the set of all rows that contain A = 4 we have Flood and Rain.
I need the values of A where for a given value 'a' in A, there exists rows with 'a' that must contain all of the following fields provided (in the example Flood and Rain).
Please let me know if you need further clarification.
I need the values of A where for a given value 'a' in A, there exists rows with 'a' that must contain all of the following fields provided (in the example Flood and Rain).
You can use aggregation, and filter with a having clause:
select a
from mytable t
where x in ('Flood', 'Rain') -- either one or the other
having count(*) = 2 -- both match
If tuples (a, x) tuples are not unique, then you want having count(distinct x) = 2 instead.
You Shooud use count(distinct X) group by A and having
count(distinct...) avoid situation where you have two time the same value for X
select A
from my_table
WHERE x in ('Flood', 'Rain')
group A
having count(distinct X) = 2
What SQLite statement do I need to get the column name WHERE there is a value?
COLUMN NAME: ALPHA BRAVO CHARLIE DELTA ECHO
ROW VALUE: 0 1 0 1 1
All I want in my return is: Bravo, Delta, Echo.
Your request is not entirely clear, but you appear to be asking for a SELECT statement that will return not data but rather columns names, and not a predictable number of values but rather a number values that depend on the data in the table.
For instance,
A B C D E
0 1 0 1 1
would return (B,D,E) whereas
A B C D E
1 0 1 0 0
would return (A, C).
If that's what you're asking, this is not something that SQL does. SQL retrieves data from the table and an SQL result set always has the same number of columns per row.
To accomplish your goal, you would have to retrieve all columns that might have a value in the table and then, in your program code, check for the value in each column and accrue a list of column names that had values.
Also, consider what happens when there is more than one row to examine and the distribution of values differ. In other words, what's the expected result if the data looks like this:
A B C D E
- - - - -
0 1 0 1 1
1 0 1 0 0
[Also, note that all the columns in your example have values, some 0, some 1. What you really want is a list of column names where the column contains a value of 1.]
Finally, consider that your inability to easily get the results you need from your data might indicate a flaw in the data model you're using. For instance, if you were to structure your data like this:
TagName TagValue
------- --------
Alpha 0
Bravo 1
Charlie 0
Delta 1
Echo 1
you could then obtain your results with SELECT TagName FROM Tags WHERE TagValue = 1.
Furthermore, if 0 and 1 are really the only two possible values (indicating boolean "presence" or "absence" of the tag) then you could remove the TagValue column and the rows for Alpha and Charlie entirely (you'd INSERT a row into the table to add tag and DELETE a row to remove it).
A design along these lines seems to model your data more accurately and allows you to entire new tags to the system without having to issue an ALTER TABLE command.
http://sqlfiddle.com/#!9/1407e/1
SELECT CONCAT(IF(ALPHA,'ALPHA,',''),
IF(BRAVO,'BRAVO,',''),
IF(CHARLIE,'CHARLIE,',''),
IF(DELTA,'DELTA,',''),
IF(ECHO,'ECHO',''))
FROM table1
I am fairly new to SQL, Big Query
I have a dataset and I want to retrieve values in column 2 corresponding to the values in column 1 if they satisfy certain conditions. I want to know how to do that. I am using Big Query Platform
Example Dataset D :
Col 1 ; Col 2
A ; 1
B ; 2
C ; 3
D ; 4
E ; 5
Query to retrieve values of col1, col2 such that col2 >2
Expected Output :
C ; 3
D ; 4
E ; 5
I am using big query platform.
According to me,
SELECT col1,col2
FROM [D]
WHERE col2>2
will give col1 and col2 as outputs where col2>2 but the values in col2 may or may not be the ones corresponding to col1.
Am I wrong ? If so, please suggest a query to get necessary output.
If you don't have a row A;5, it won't ever exist in your return. The only time you need to worry about the mismatch is if you're doing a join between one data set of {A, B, C, D, E} and another of {1, 2, 3, 4, 5}. Then every possible combination from A;1, A;2... to ...E;4, E;5 would be output, and filtering on col2 > 2 would produce A;3, B;3, C;3, ..., etc. But that isn't how your data is set up in your question, so don't worry. If you wonder how a select query will work, it's usually okay to just run it, unless it will take hours and consume tons of resources and you have a budget... but it seems more like you're doing homework.
Also don't ask for homework help on stack overflow.
Trying to wrap my head around how to do this query - I want to return a list of client records and need to exclude clients if they had only a specific value and no other values.
For example
c# value
1 X
1 Y
2 X
3 Y
I want all the records for clients 1 and 3, since they had a value other than X. I do not want client 2, because that client had ONLY X.
I for example want returned in this case:
1 X
1 Y
3 Y
Of course, I could have lots of other records with other client id's and values, but I want to eliminate only the ones that have a single "X" value and no other values.
Maybe using a sub-query?
Try this:
SELECT client, value FROM myTable where `client` in
(select distinct(client) from myTable where value !='X');
Returns:
Client Value
1 X
1 Y
3 Y
Something like this
SELECT ABB2.*
FROM
mytable AS ABB2
JOIN
(SELECT c
FROM mytable
WHERE value <> "X"
GROUP BY c) AS ABB1 ON ABB1.c = ABB2.c
GROUP BY ABB2.c, ABB2.value
It's faster than using a WHERE clause to identify the sub query results (as in Mike's answer)
I have a strange query to perform from a website. I have sets of arrays that contain pertinent ids from a many tables - 1 table per array. For example (the array name is the name of the table):
Array Set 1:
array "q": 1,2,3
array "u": 1,5
array "k": 7
Array Set 2:
array "t": 2,12
array "o": 8, 25
Array Set 3 (not really a set):
array "e": 5
I have another table, Alignment, which is not represented by the arrays. It performs a one to many relationship, allowing records from tables q,u, and k (array set 1, and recorded as relType/relID in the table) to be linked to records from t and o (array set 2, recorded as keyType/keyID) and e (array set 3, recorded as keyType/keyID). Example below:
Table: Alignment
id keyType keyID relType relID
1 e 5 q 1
2 o 8 q 1
3 o 8 u 1
4 t 2 q 2
5 t 2 k 7
6 t 12 q 1
So, in record 6, a record with an id of 12 from table t is being linked to a record with an id of 1 from table q.
I have to find missing links. The ideal state is that each of the ids from array set 1 have a record in the alignment table linking them to at least 1 record from array set 2. In the example, alignment record 1 does not count towards this goal, because it aligns a set 1 id to a set 3 id (instead of set 2).
Scanning the table, you can quickly see that there are some missing ids from array set 1: "q"-3 and "u"-5.
I've been doing this with script, by looping through each set 1 array and looking for a corresponding record, which generates a whole bunch of sql calls and really kills any page that calls this function.
Is there some way I could accomplish this in a single sql statement?
What would I like the results to look like (ideally):
recordset (consisting magically of data that didn't exist in the table):
relType | relID
q 3
u 5
However, I would be elated with even a binary type answer from the database - were all the proper ids found: true or false? (Though the missing records array is required for other functions, but at least I'd be able to choose between the fast and slow options).
Oh, MySQL 5.1.
User Damp gave me an excellent answer using a temporary table, a join, and an IS NULL statement. But it was before I added in the wrinkle that there was a third array set that needed to be excluded from the results, which also ruins the IS NULL part. I edited his sql statement to look like this:
SELECT *
FROM k2
LEFT JOIN alignment
USING ( relType, relID )
HAVING alignment.keyType IS NULL
OR alignment.keyType = "e"
I've also tried it with a Group By relID (i always thought that was a requirement of the HAVING clause). The problem is that my result set includes "q"-1, which is linked to all three types of records ("o","t", and "e"). I need this result excluded, but I'm not sure how.
Here's the sql I ended up with:
SELECT *
FROM k2
LEFT JOIN (
SELECT *
FROM alignment
WHERE keyType != 'e' and
(
(relType = 'q' AND relID IN ( 1, 2, 3 ))
OR
(relType = 'u' AND relID IN ( 1, 5 ))
OR
(relType = 'k' AND relID IN ( 7 ))
)
)A
USING ( relType, relID )
HAVING keyType Is Null
I have to dump the values for the IN qualifiers with script. The key was not to join to the alignment table directly.
You can try to go this route:
DROP TABLE IF EXISTS k2;
CREATE TEMPORARY TABLE k2 (relType varchar(10),relId int);
INSERT INTO k2 VALUES
('q',1),
('q',2),
('q',3),
('u',1),
('u',5),
('k',7);
SELECT * FROM k2
LEFT JOIN Alignment USING(relType,relId)
HAVING Alignment.keyType IS NULL
This should work well for small tables. Not sure about very large ones though...
EDIT
If you wanted to add a WHERE statement the query would be as follow
SELECT * FROM k2
LEFT JOIN Alignment USING(relType,relId)
WHERE Alignment.keyType != 'e'
HAVING Alignment.keyType IS NULL