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hello I would like to find a solution to solve my problem in a single request if possible.
For the moment I take all the records then I go through the lines one by one to eliminate what I don't want.
I have 2 tables : first table with links
the second with the prefered label for the url
the second table must be consulted keeping only the row with maximum priority
priority rules are
the current user then
the user group and finally
everyone.
if the hidden column is true, exclude any reference to the url
here is the expected result.
Unfortunately, I don't see any other solution than to multiply the conditions on several selects and unions.
if you have a idea to solve my problem, thank you in advance for your help
It appears as though you can rely on pref_id for the preference ordering, correct? If so, you could try:
SELECT *
FROM table2
INNER JOIN table1 ON table2.url_id = table1.url_id
QUALIFY ROW_NUMBER() OVER (
PARTITION BY table1.url
ORDER BY pref_id ASC
) = 1
This will partition by the url and then provide only the one with lowest pref_id.
I didn't test this SQL as I wasn't sure which RDBMS you're running on, but I used Rasgo to translate the SQL.
maybe of interest in this tricky query:
select so.*, table1.url from
(select distinct t.url_id,
(select pref_id from table2 s where s.url_id = t.url_id order by "user" is null, "group" is null limit 1) pref_id
from table2 t
where not exists(select 1 from table2 s where s.hide and s.url_id = t.url_id)
) ids
join table2 so on so.pref_id = ids.pref_id
join table1 ON table1.url_id = ids.url_id
order by so.url_id;
here is my solution but i think there is better to do.
in the condition's select, I built a column which gives a level note according to the priorities
DECLARE #CUR_USER VARCHAR(10) = 'ROBERT'
DECLARE #CUR_GROUP VARCHAR(10) = 'DEV'
DECLARE #TABLE1 TABLE (
URL_ID INT
,URLNAME VARCHAR(100)
);
DECLARE #TABLE2 TABLE (
PREF_ID INT
,URL_ID INT
,FAVORITE_LABEL VARCHAR(100)
,USER_GROUP VARCHAR(10)
,USER_CODE VARCHAR(10)
,HIDE_URL DECIMAL(1, 0) DEFAULT 0
);
INSERT INTO #TABLE1
VALUES
(1, 'https://stackoverflow.com/')
,(2, 'https://www.microsoft.com/')
,(3, 'https://www.apple.com/')
,(4, 'https://www.wikipedia.org/')
;
INSERT INTO #TABLE2
VALUES
(1000, 1, 'find everything', NULL, 'ROBERT', 0)
,(1001, 1, 'a question ? find the answer here', 'DEV', NULL, 0)
,(1002, 1, 'StackOverFlow', NULL, NULL, 0)
,(1003, 2, 'Windows', 'DEV', NULL, 0)
,(1004, 2, 'Microsoft', NULL, NULL, 0)
,(1005, 3, 'Apple', NULL, NULL, 0)
,(1006, 4, 'Free encyclopedia', NULL, 'ROBERT', 1)
,(1007, 4, 'Wikipedia', NULL, NULL, 0)
,(1008, 1, 'StackOverFlow FOR MAT', 'MAT', NULL, 0)
,(1009, 2, 'Microsoft FOR MAT', 'MAT', NULL, 0)
,(1010, 3, 'Apple', 'MAT', NULL, 1)
,(1011, 4, 'Wikipedia FOR MAT', 'MAT', NULL, 0)
,(1012, 1, 'StackOverFlow', NULL, 'JEAN', 1)
,(1013, 2, 'Microsoft ', NULL, 'JEAN', 0)
,(1014, 3, 'Apple', NULL, 'JEAN', 0)
,(1015, 4, 'great encyclopedia', NULL, 'JEAN', 0)
;
SELECT t2.* ,t1.URLName
FROM #TABLE1 t1
INNER JOIN #TABLE2 t2 ON t1.URL_ID = t2.URL_ID
WHERE EXISTS (
SELECT 1
FROM (
SELECT TOP (1) test.PREF_ID
,CASE
-- if I do not comment this case: jean from the MAT group will not see apple
-- WHEN Hide_Url = 1
-- THEN 3
WHEN USER_code IS NOT NULL
THEN 2
WHEN USER_GROUP IS NOT NULL
THEN 1
ELSE 0
END AS ROW_LEVEL
FROM #TABLE2 test
WHERE (
(
test.USER_GROUP IS NULL
AND test.user_group IS NULL
AND test.USER_code IS NULL
)
OR (test.USER_GROUP = #CUR_GROUP)
OR (test.USER_code = #CUR_USER)
)
AND t2.URL_ID = test.URL_ID
ORDER BY ROW_LEVEL DESC
) test
WHERE test.PREF_ID = t2.PREF_ID
AND Hide_Url = 0
)
Simply use an ORDER BY clause that puts the preferred row first. You can use this in the window function ROW_NUMBER and work with this or use a lateral top(1) join with CROSS APPLY.
select *
from urls
cross apply
(
select top(1) *
from labels
where labels.url_id = urls.url_id
where [Group] is not null or [user] is not null or hide is not null
order by
case when [Group] is null then 2 else 1 end,
case when [user] is null then 2 else 1 end,
case when hide is null then 2 else 1 end
) top_labels
order by urls.url_id;
I have a small DSL where user can express certain conditions for some actions. Now i need to resolve those conditions on sql server.
The nodes in condition are AND/OR/ atom, where AND/OR are binary expressions and atom is Identifier == Operand, with == being the only operator.
So i created following table in Sql Server to store the tree.
CREATE TABLE [dbo].[Condition]([Id] [hierarchyid], [Order] [int] NULL,
[NodeType] [nchar](10),[Identifier] [nvarchar](50) ,[Operand] [nvarchar](255) NULL)
Is there any way to walk this tree and eval its node in a sql statement ? I can do this in C# with compiled code, but i am stuck thinking about it in sql. I need it in sql because the filtering of data has to happen in sql.
for example if condition is
(T=="T1" || T=="T2") && (R=="R1" || R =="R2") || T=="T3"
The table will look like
Id Order NodeType Identifier Operand Id.ToString()
------------------------------------------------------------------------------------
0x NULL OR NULL NULL /
0x58 1 AND NULL NULL /1/
0x5AC0 1 OR NULL NULL /1/1/
0x5AD6 1 Expr T T1 /1/1/1/
0x5ADA 2 Expr T T2 /1/1/2/
0x5B40 2 OR NULL NULL /1/2/
0x5B56 1 Expr R R1 /1/2/1/
0x5B5A 2 Expr R R2 /1/2/2/
0x68 2 Expr T T3 /2/
Since we don't know the values of the terms until we evaluate them, we need to do this from the bottom up. In code, we have a stack that can keep track of where we are. I didn't really want to build a stack, so I evaluated all the terms from the bottom up.
I tried to do this with a CTE, but failed. I couldn't get both of the terms in the recursive member of the CTE. Hence, I had to write my own loop.
There's a table holding all the intermediate values #I. Each loop we get closer to the top of the tree. When we have the value of the root node, we are done. We'll also be clearing out the unnecessary rows so that at the end, we just have one row.
Here's the schema:
CREATE TABLE [dbo].[Condition](
[Id] hierarchyid,
[Order] [int] NULL,
[NodeType] [nchar](10),
[Identifier] [nvarchar](50),
[Operand] [nvarchar](255) NULL);
insert Condition (id, "Order", NodeType, Identifier, Operand) values
(0x, null, 'OR', null, null),
(0x58, 1, 'AND', null, null),
(0x5ac0, 1, 'OR', null, null),
(0x5ad6, 1, 'Expr', 'T', 'T1'),
(0x5ada, 2, 'Expr', 'T', 'T2'),
(0x5b40, 2, 'OR', null, null),
(0x5b56, 1, 'Expr', 'R', 'R1'),
(0x5b5a, 2, 'Expr', 'R', 'R2'),
(0x68, 2, 'Expr', 'T', 'T3');
Here's the code assuming that #T and #R are the identifiers we are looking at:
declare #T varchar(max) = 'T1';
declare #R varchar(max) = 'R1';
declare #I table (
id hierarchyId,
"order" int,
value bit
);
insert #I (id, "order", value)
select id, "order", case when operand =
case when identifier = 'T' then #T when identifier = 'R' then #R end
then 1 else 0 end
from condition
where nodetype = 'Expr';
while not exists (select * from #I where id = 0x) begin
insert #I (id, "order", value)
select node.id, node."order",
case
when nodetype = 'AND' then
case when L.value = 1 and R.value = 1 then 1 else 0 end
when nodetype = 'OR' then
case when L.value = 1 or R.value = 1 then 1 else 0 end
end
from condition node
join #I L on L.id.GetAncestor(1) = node.id and L."order" = 1
join #I R on R.id.GetAncestor(1) = node.id and R."order" = 2
delete from #I where id.GetAncestor(1) in (select id from #I)
end
select *, id.ToString() from #I
Here's the fiddle: http://sqlfiddle.com/#!6/8e5cc/1
Oracle Counting Null, both of them are returning same result, but which is more recommended? or is there better way?
COUNT(DECODE(RESP_CD, NULL, 'X'))
vs
NVL(SUM(DECODE(RESP_CD, NULL, 1, 0)), 0)
SELECT SUM(n_count), SUM(x_count)
FROM
(SELECT CASE WHEN resp_cd IS NULL THEN 1 END n_count,
CASE WHEN resp_cd = 'x' THEN 1 END x_count
FROM your_table
);
I was wondering if I have SQL Server 2008 table that was created like this:
CREATE TABLE tbl (id INT PRIMARY KEY,
dvt NVARCHAR(32),
d0 TINYINT,
d1 TINYINT,
d2 TINYINT);
INSERT INTO tbl (id, dvt, d0, d1, d2)
VALUES(1, '1', NULL, NULL, NULL);
INSERT INTO tbl (id, dvt, d0, d1, d2)
VALUES(2, '', NULL, NULL, NULL);
INSERT INTO tbl (id, dvt, d0, d1, d2)
VALUES(3, '2,5', NULL, NULL, NULL);
INSERT INTO tbl (id, dvt, d0, d1, d2)
VALUES(4, '13, 34, 45, 5', NULL, NULL, NULL);
INSERT INTO tbl (id, dvt, d0, d1, d2)
VALUES(5, '1,8, 10', NULL, NULL, NULL);
I need to take the string from the 'dvt' column and split it into 'd0', 'd1' and 'd2' columns. The 'dvt' value can be separated by commas.
I can do this using C# and a tokenization function but I was wondering if it's possible to do the same using SQL?
Columns BEFORE:
1, "1", NULL, NULL, NULL
2, "", NULL, NULL, NULL
3, "2,5", NULL, NULL, NULL
4, "13, 34, 45, 5", NULL, NULL, NULL
5, "1,8, 10", NULL, NULL, NULL
Columns AFTER:
1, "1", 1, NULL, NULL
2, "", NULL, NULL, NULL
3, "2,5", 2, 5, NULL
4, "13, 34, 45, 5", 13, 34, 45 -- 5 is discarded
5, "1,8, 10", 1, 8, 10
The main problem with this type of code is re-use of calculations.
SQL Server is good at caching results (If you type the exact same CHARINDEX() caluculation 5 times, it only calculates once and re-uses that result 4 times).
That's little consolation for the poor coder who has to type or maintain that code though.
SQL Server 2005 onward has CROSS APPLY that does help somewhat. The logic is repeated, but the results can be referenced repeatedly, rather that the calculation typed repeatedly.
SELECT
*,
SUBSTRING(dvt, 1, ISNULL(comma1.pos-1, LEN(dvt)) ) AS item1,
SUBSTRING(dvt, comma1.pos+1, ISNULL(comma2.pos-1, LEN(dvt))-comma1.pos) AS item2,
SUBSTRING(dvt, comma2.pos+1, ISNULL(comma3.pos-1, LEN(dvt))-comma2.pos) AS item3
FROM
(
SELECT 'ab,c,def,hij' AS dvt
UNION ALL
SELECT 'xyz,abc' AS dvt
)
AS data
OUTER APPLY
(SELECT NULLIF(CHARINDEX(',', data.dvt, 1 ), 0) AS pos ) AS comma1
OUTER APPLY
(SELECT NULLIF(CHARINDEX(',', data.dvt, comma1.pos+1), 0) AS pos WHERE comma1.pos > 0) AS comma2
OUTER APPLY
(SELECT NULLIF(CHARINDEX(',', data.dvt, comma2.pos+1), 0) AS pos WHERE comma2.pos > 0) AS comma3
OUTER APPLY
(SELECT NULLIF(CHARINDEX(',', data.dvt, comma3.pos+1), 0) AS pos WHERE comma3.pos > 0) AS comma4
Another option is to simply write a table valued user defined function that does this (even when the result of the function is always one row). Then you simply CROSS APPLY that function.
Try something like this
;WITH Vals AS (
SELECT id,
dvt,
CAST('<r>'+REPLACE(dvt,',','</r><r>')+'</r>' AS XML).query('/r[1]').value('.','varchar(max)') d1,
CAST('<r>'+REPLACE(dvt,',','</r><r>')+'</r>' AS XML).query('/r[2]').value('.','varchar(max)') d2,
CAST('<r>'+REPLACE(dvt,',','</r><r>')+'</r>' AS XML).query('/r[3]').value('.','varchar(max)') d3
FROM tbl
)
SELECT id,
dvt,
CASE WHEN d1 = '' THEN NULL ELSE d1 END d1,
CASE WHEN d2 = '' THEN NULL ELSE d2 END d2,
CASE WHEN d3 = '' THEN NULL ELSE d3 END d3
FROM Vals
It's possible.
You could do it with some repetitive calls to CHARINDEX and checking for nulls but it may be better and clearer to write a FUNCTION to split the string.
I needed String tokenizer for Sybase; separation by 1 or more spaces in name data
Name date clean and has no commas or other special characters
declare #test varchar(60)
select #test=str_replace(lower(rtrim('Jayanta Narayan Choudhuri'))," ",",")
exec sp_splitwords #test
This is based on a neat hint by Kenny Lucas from http://www.sql9.com/?id=102
drop proc sp_splitwords
go
create proc sp_splitwords(#instr varchar(80)) as
begin
declare #pos int,
#word varchar(80),
#list varchar(81)
create table #words(word varchar(80))
select #list = #instr + ','
set #pos = patindex('%,,%',#list)
while #pos > 0
begin
select #list = str_replace(#list,',,',',')
set #pos = patindex('%,,%',#list)
end
set #pos = patindex('%,%',#list)
while #pos > 0
begin
set #word = substring(#list, 1,#pos-1)
set #list = substring(#list, #pos+1,len(#list)-#pos)
if NOT( #word is null OR LEN(#word) = 0 )
insert into #words (word) values (#word)
set #pos = patindex('%,%',#list)
end
select * from #words
order by len(word) desc
drop table #words
end
I could port Metaphone SQL Function to Sybase
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=125724
Sybase allows recursion in functions from a beautiful workaround
http://www.sypron.nl/quiz2008a.html#jan08
CREATE FUNCTION Metaphone2 (#str VARCHAR(100))
RETURNS VARCHAR(25) AS
BEGIN
RETURN #str
END
DROP FUNCTION Metaphone2
GO
CREATE FUNCTION Metaphone2 (#str VARCHAR(100))
RETURNS VARCHAR(25) AS
BEGIN
RETURN dbo.Metaphone(#str)
END
Changed 1 line of Function pasted from http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=125724
Combination of metaphone and string tokenizer means I can fuzzy search names
first middle and surname and rotations thereof
I have got the following query:
WITH data AS(
SELECT * FROM partstat WHERE id=4
)
SELECT id, AVG(Value) AS Average
FROM (
SELECT id,
AVG(column_1) as column_1,
AVG(column_2) as column_2,
AVG(column_3) as column_3
FROM data
GROUP BY id
) as pvt
UNPIVOT (Value FOR V IN (column_1,column_2,column_3)) AS u
GROUP BY id
if column_1,column_2 and column_3 (or one of this columns) have values then i get result as the following:
id, Average
4, 5.12631578947368
if column_1,column_2 and column_3 have NULL values then the query does not return any rows as the following:
id, Average
my question is how can i get as the following result if columns contents NULL values?
id, Average
4, NULL
Have you tried using COALESCE or ISNULL?
e.g.
ISNULL(AVG(column_1), 0) as column_1,
This does mean that you will get 0 as the result instead of 'NULL' though - do you need null when they are all NULL?
Edit:
Also, is there any need for an unpivot? Since you are specifying all 3 columns, why not just do:
SELECT BankID, (column_1 + column_2 + column_3) / 3 FROM partstat
WHERE bankid = 4
This gives you the same results but with the NULL
Of course this is assuming you have 1 row per bankid
Edit:
UNPIVOT isn't supposed to be used like this as far as I can see - I'd unpivot first then try the AVG... let me have a go...
Edit:
Ah I take that back, it is just a problem with NULLs - other posts suggest ISNULL or COALESCE to eliminate the nulls, you could use a placeholder value like -1 which could work e.g.
SELECT bankid, AVG(CASE WHEN value = -1 THEN NULL ELSE value END) AS Average
FROM (
SELECT bankid,
isnull(AVG(column_1), -1) as column_1 ,
AVG(Column_2) as column_2 ,
Avg(column_3) as column_3
FROM data
group by bankid
) as pvt
UNPIVOT (Value FOR o in (column_1, column_2, column_3)) as u
GROUP BY bankid
You need to ensure this will work though as if you have a value in column2/3 then column_1 will no longer = -1. It might be worth doing a case to see if they are all NULL in which case replacing the 1st null with -1
Here is an example without UNPIVOT:
DECLARE #partstat TABLE (id INT, column_1 DECIMAL(18, 2), column_2 DECIMAL(18, 2), column_3 DECIMAL(18, 2))
INSERT #partstat VALUES
(5, 12.3, 1, 2)
,(5, 2, 5, 5)
,(5, 2, 2, 2)
,(4, 2, 2, 2)
,(4, 4, 4, 4)
,(4, 21, NULL, NULL)
,(6, 1, NULL, NULL)
,(6, 1, NULL, NULL)
,(7, NULL, NULL, NULL)
,(7, NULL, NULL, NULL)
,(7, NULL, NULL, NULL)
,(7, NULL, NULL, NULL)
,(7, NULL, NULL, NULL)
;WITH data AS(
SELECT * FROM #partstat
)
SELECT
pvt.id,
(ISNULL(pvt.column_1, 0) + ISNULL(pvt.column_2, 0) + ISNULL(pvt.column_3, 0))/
NULLIF(
CASE WHEN pvt.column_1 IS NULL THEN 0 ELSE 1 END +
CASE WHEN pvt.column_2 IS NULL THEN 0 ELSE 1 END +
CASE WHEN pvt.column_3 IS NULL THEN 0 ELSE 1 END
, 0)
AS Average
FROM (
SELECT id,
AVG(column_1) as column_1,
AVG(column_2) as column_2,
AVG(column_3) as column_3
FROM data
GROUP BY id
) as pvt