I’m attempting to count records that match specific criteria, including one field being null, but including the null clause results in no records being found.
If I output the contents of the field, it comes back as “(null)”. I’ve tried IS NULL and ISNULL, both of which appear that they should work when looking at other sources, but they both fail for me.
SELECT calls.contact_number, calls.contact_name, COUNT(notes.id) AS note_count
FROM calls LEFT JOIN notes on calls.id = notes.call_id
WHERE calls.contact_number = "123" AND notes.group_id ISNULL
GROUP BY calls.contact_number
This returns no records, whereas I’m expecting it to return one.
Move the condition in the ON clause:
SELECT calls.contact_number, calls.contact_name, COUNT(notes.id) AS note_count
FROM calls LEFT JOIN notes
ON calls.id = notes.call_id AND notes.group_id IS NULL
WHERE calls.contact_number = "123"
GROUP BY calls.contact_number, calls.contact_name
After grabbing a copy of the database, the notes.group_id field was determined to be an integer type, and the record in question actually contained a 0.
The successful query ended up being
SELECT calls.contact_number, calls.contact_name, COUNT(notes.id) as note_count
FROM calls LEFT JOIN notes
ON calls.id = notes.call_id
WHERE calls.contact_number = “123” AND (notes.group_id IS NULL OR notes.group_id = 0)
GROUP BY calls.contact_number
Not sure why the NSLog output of the returned value for group_id was ‘(null)’, some weird conversion?
Related
I need to merge some randomly uppercased data that has been collected in an SQLite table key_val, such that key is always lowercase and no vals are lost. There is a unique compound index on key,val.
The initial data looks like this:
key|val
abc|1
abc|5
aBc|1
aBc|5
aBc|3
aBc|2
AbC|1
abC|3
The result after the merge would be
key|val
abc|1
abc|2
abc|3
abc|5
In my programmer brain, I would
for each `key` with upper case letters;
if a lower cased `key` is found with the same value
then delete `key`
else update `key` to lower case
Re implementing the loop has a sub query for each row found with upper case letters, to check if the val already exists as a lower case key
If it does, I can delete the cased key.
From there I can UPDATE key = lower(key) as the "duplicates" have been removed.
The first cut of the programming method of finding the dupes is:
SELECT * FROM key_val as parent
WHERE parent.key != lower(parent.key)
AND 0 < (
SELECT count(s.val) FROM key_val as s
WHERE s.key = lower(parent.key) AND s.val = parent.val
)
ORDER BY parent.key DESC;
I'm assuming there's a better way to do this in SQLite? The ON CONFLICT functionality seems to me like it should be able to handle the dupe deletion on UPDATE but I'm not seeing it.
First delete all the duplicates:
DELETE FROM key_val AS k1
WHERE EXISTS (
SELECT 1
FROM key_val AS k2
WHERE LOWER(k2.key) = LOWER(k1.key) AND k2.val = k1.val AND k2.rowid < k1.rowid
);
by keeping only 1 combination of key and val with the min rowid.
It is not important if you kept the key with all lower chars or not, because the 2nd step is to update the table:
UPDATE key_val
SET key = LOWER(key);
See the demo.
Honestly it might just be easier to create a new table and then insert into it. As it seems you really just want a distinct select here, use:
INSERT INTO kev_val_new ("key", val)
SELECT DISTINCT LOWER("key"), val
FROM key_val;
Once you have populated the new table, you may drop the old one, and then rename the new one to the previous name:
DROP TABLE key_val;
ALTER TABLE key_val_new RENAME TO key_val;
I agree with #Tim that it would be easire to re-create table using simple select distict lower().. statement, but that's not always easy if table has dependant objects (indexes, triggers, views). In this case this can be done as sequence of two steps:
insert lowered keys which are not still there:
insert into t
select distinct lower(tr.key) as key, tr.val
from t as tr
left join t as ts on ts.key = lower(tr.key) and ts.val = tr.val
where ts.key is null;
now when we have all lowered keys - remove other keys:
delete from t where key <> lower(key);
See fiddle: http://sqlfiddle.com/#!5/84db50/11
However this method assumes that key is always populated (otherwise it would be a strange key)
If vals can be null then "ts.val = tr.val" should be replaced with more complex stuff like ifnull(ts.val, -1) = ifnull(tr.val, -1) where -1 is some unused value (can be different). If we can't assume any unused value like -1 then it should be more complex check for null / not null cases.
I have the following columns in a SQLite DB.
id,ts,origin,product,bid,ask,nextts
1,2016-10-18 20:20:54.733,SourceA,Dow,1.09812,1.0982,
2,2016-10-18 20:20:55.093,SourceB,Oil,7010.5,7011.5,
3,2016-10-18 20:20:55.149,SourceA,Dow,18159.0,18161.0,
How can I populate the 'next timestamp' column (nextts) with the next timestamp for the same product (ts), from the same source? I've been trying the following, but I can't seem to put a subquery in an UPDATE statement.
UPDATE TEST a SET nextts = (select ts
from TEST b
where b.id> a.id and a.origin = b.origin and a.product = b.product
order by id asc limit 1);
If I call this, I can display it, but I haven't found a way of updating the value yet.
select a.*,
(select ts
from TEST b
where b.id> a.id and a.origin = b.origin and a.product = b.product
order by id asc limit 1) as nextts
from TEST a
order by origin, a.id;
The problem is that you're using table alias for table in UPDATE statement, which is not allowed. You can skip alias from there and use unaliased (but table-name prefixed) reference to its columns (while keeping aliased references for the SELECT), like this:
UPDATE TEST
SET nextts = (
SELECT b.ts
FROM TEST b
WHERE b.id > TEST.id AND
TEST.origin = b.origin AND
TEST.product = b.product
ORDER BY b.id ASC
LIMIT 1
);
Prefixing unaliased column references with the table name is necessary for SQLite to identify that you're referencing to unaliased table. Otherwise the id column whould be understood as the id from the closest[*] possible data source, in which case it's the aliased table (as b alias), while we're interested in the unaliased table, therefore we need to explicitly tell SQLite that.
[*] Closest data source is the one listed in the same query, or parent query, or parent's parent query, etc. SQLite is looking for the first data source (going from inner part to the outside) in the query hierarchy that defines this column.
I have an ASP.NET Web API app using Oracle's Entity Framework driver. I have an entity defined for a view as follows:
CREATE OR REPLACE FORCE VIEW "PHASE_TWO"."EDIPRODUCT" ("ID", "STK_NUM", "TITLE", "ISBN", "UPC", "ITEMNO", "LONGFORMAT", "ABRIDGED", "WEB_TITLES_ID", "OCLC", "GENRE", "RELYEAR", "ORIG_REL", "LANG", "ORIG_STKNUM", "PUBLISHER", "PEOPLELIST", "SALES_ORG", "NOT_AVAIL") AS
SELECT sap_product.id,
sap_product.stk_num,
sap_product.longdesc AS title,
sap_product.isbn,
sap_product.upc,
sap_product.itemno,
sap_product.longformat,
sap_product.abridged,
mwt_product.web_titles_id,
mwt_product.oclc,
mwt_product.genre,
mwt_product.RELYEAR,
sap_product.orig_rel,
sap_product.lang,
sap_product.orig_stknum,
UPPER (publisher.name) publisher,
(SELECT LISTAGG (p.FULLNAME, ', ') WITHIN GROUP (
ORDER BY pp.rank) AS People
FROM people p
JOIN product_people pp
ON p.id = pp.peopleid
WHERE pp.stk_num = sap_product.stk_num
GROUP BY pp.STK_NUM
) PeopleList,
sppg.PRICING_TYPE as sales_org,
sap_product.not_avail
FROM sap_product
JOIN mwt_product ON sap_product.stk_num = mwt_product.stk_num
JOIN publisher ON mwt_product.publisherid = publisher.id
JOIN SAP_PRODUCT_PRICING_GROUP sppg on sppg.STK_NUM = mwt_product.stk_num and sppg.MARKED_FOR_DELETION = 0
WHERE mwt_product.WEB_PRODUCTS_ID > 0;
This view works as expected in SQL Developer. My getEDIPRODUCT function (yes, it's VB.NET) in my controller is as follows:
' GET: odata/EDIPRODUCTs
<EnableQuery>
Function GetEDIPRODUCT() As IQueryable(Of EDIPRODUCT)
Dim results As IQueryable
results = db.EDIPRODUCT
For Each _product In results
Console.Write(_product)
Next
Return results
End Function
I just added the for loop in order to inspect the results. What I see when I inspect the results is the same product record is returned for each row. The value for the ID is duplicate and the only other field that should have variant values (sppg.PRICING_TYPE as sales_org) also just repeats.
I have other views where this does not occur. The correct number of records are always returned, but the first record retrieved is always just repeated in each row of the result set. Any idea what could be going on here?
I never actually resolved this issue and am still interested in why this fails, but I rewrote the portion of the app that uses this view to use OData's $expand to retrieve the related data.
Struggling with a simple problem and find no solution.
https://ideone.com/Hisu8H (sqlfiddle mini) Should be two rows, but only one OK appears.
If there is a record there should be an OK result. If no records there should be ERROR result.
SELECT
CASE WHEN (SELECT count(*) from code)=0 THEN 'ERROR' else 'OK' end
FROM code
WHERE "CODE_ID"='EXISTS'
The problem is that if the CODE_ID exists, there will be a line OK but if the record is missing there will be no line fetched at all.
In a simple query this works. But not as a condition!
SELECT COALESCE(count(*), 0) FROM code
WHERE "CODE_ID"='ERROR'
Thanks in advance for any clue!
If there is no row that matches the condition then nothing is returned and you can't count it.
To return information about values that are used in a condition but do not exist in the database you typically use an outer join on the list of values:
select t.id,
code.code_id
from (
values ('error'), ('test')
) as t (id)
left join code on code.code_id = t.id;
This essentially a where code_id in ('error', 'test') query that also returns those values from the in list that do not exist in the table.
This can then be used to identify the missing values:
select t.id,
case when code.code_id is null then 'Error' else 'OK' end as status
from (
values ('error'), ('test')
) as t (id)
left join code on code.code_id = t.id;
I have a MySQL table Page with 2 columns: PageID and OrderByMethod.
I also then have a Data table with lots of columns including PageID (the Page the data is on), DataName, and DataDate.
I want OrderByMethod to have one of three entries: Most Recent Data First, Most Recent Data Last, and Alphabetically.
Is there a way for me to tack an "ORDER BY" clause to the end of this query that will vary its ordering method based on the contents of the "OrderByMethod" column? For example, in this query, I would want to have the ORDER BY clause contain whatever ordering rule is stored in Page 1's OrderByMethod column.
GET * FROM `Data` WHERE `Data`.`PageID`=1 ORDER BY xxxxxx;
Maybe a SELECT clause in the ORDER BY clause? I'm not sure how that would work though.
Thanks!
select Data.*
from Data
inner join Page on (Data.PageID=Page.PageID)
where Data.PageID=1
order by
if(Page.OrderByMethod='Most Recent Data First', now()-DataDate,
if(Page.OrderByMethod='Most Recent Data Last', DataDate-now(), DataName)
);
You can probably do this with the IF syntax to generate a column that you can then order by.
SELECT *, IF(Page.OrderBy = 'Alphabetically', Data.DataName, IF(Page.OrderBy = 'Most Recent Data First', NOW() - Data.DataDate, Data.DataDate - NOW())) AS OrderColumn
FROM Data
INNER JOIN Page ON Data.PageID = Page.PageID
WHERE Page.PageID = 1
ORDER BY OrderColumn
The direction of the ordering is determined in the calculation of the data instead of specifying a direction in the ORDER BY
Can you just append the order by clause to the select statement and rebind the table on postback?
If you want to use the content of the column in Page table as an expression in ORDER BY you have to do it using prepared statements. Let say, you store in OrderByMethod something like "field1 DESC, field2 ASC" and you want this string to be used as it is:
SET #order_by =(SELECT OrderByMethod FROM Page WHERE id = [value]);
SET #qr = CONCAT(your original query,' ORDER BY ', #order_by);
PREPARE stmt FROM #qr;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
If you want the result set to be sorted based on the value of OrderByMethod , you can use IF as it was already mentioned by others, or CASE :
...
ORDER BY
CASE OrderByMethod
WHEN 'val1' THEN field_name1
WHEN 'val2' THEN field_name2
....etc
END