Hej folks,
it is driving me crazy. I'll try to concat some values from one table to use it in a where clause in another statement. It's like this script.
LIB CONNECT TO 'MSSQLSERVER';
TempTab:
Load KST;
SQL SELECT KST FROM vKST WHERE Region = 'Driver';
Let Test = Concat(distinct KST, ',');
drop Table TempTab;
// ...
LIB CONNECT TO 'ORACLESERVER';
Foo:
Load *;
SQL SELECT Value FROM KSTvalues WHERE KST IN ($(Test));
My problem is that the variable "Test" is only calculated to null. Has anyone a working idea for this?
In this case Concat function should be used in context of a table in order to get all the values from a field.
So to get all values you'll have to load them in a temp table first and in it to perform the concatenation. And then use variable to get the resulted field value.
Have a look at the script below. The concatenation is performed in TempTable and then using peek function to get the value of ConcatField into vConcatValues variable (im dropping the TempTable at the end because its not needed once the variable is populated)
TempTable will have the following content:
And vConcatValues will be:
RawData:
Load * inline [
Values
Value1
Value1
Value2
Value3
Value4
Value5
];
TempTable:
Load
Concat(distinct Values, ',') as ConcatField
Resident
RawData
;
let vConcatValues = peek('ConcatField');
// We dont need the TempTable anymore and can be dropped
Drop Table TempTable;
P.S. probably the sql clause will raise an error, because the values will not be defined as strings. In this case you can use something like this:
TempTable:
Load
Concat(distinct Values, '","') as ConcatField
Resident
Raw
;
Using "," as separator will result in Value1","Value2","Value3","Value4", "Value5 (see the missing " in front and in the end)
We'll have to tweak the variable a bit to fix this:
let vConcatValues = '"' & peek('ConcatField') & '"';
And the result then will be:
"Value1","Value2","Value3","Value4", "Value5"
Related
We are using PostgREST to automatically generate a REST API for a Postgres database. Our primary keys have an external representation that's different from how we store them internally. For simplicity's sake lets pretend the ids are stored as integers but we represent them as hexadecimal strings outwardly.
It's simple enough to get PostgREST to convert to the external representation for read operations:
CREATE DOMAIN hexid AS bigint;
CREATE TABLE fruits (
fruit_id hexid PRIMARY KEY,
name text
);
CREATE OR REPLACE VIEW api_fruits AS
SELECT to_hex(fruit_id) as fruit_id, name FROM fruits;
INSERT INTO fruits(fruit_id, name) VALUES('51955', 'avocado');
PostgREST generates the expected representation when we GET api_fruits:
[
{
"fruit_id": "caf3",
"name": "avocado"
}
]
But that's about as far as we get with this solution. It's a one way transformation so we won't be able to POST/PATCH records this way. The way PostgREST works is to transform such requests into equivalent INSERT and UPDATE statements. But this view with its custom formatting is not updatable. This is what would happen if we tried:
ERROR: cannot insert into column "fruit_id" of view "api_fruits"
DETAIL: View columns that are not columns of their base relation are not updatable.
STATEMENT: WITH pgrst_source AS (WITH pgrst_payload AS (SELECT $1::json AS json_data), pgrst_body AS ( SELECT CASE WHEN json_typeof(json_data) = 'array' THEN json_data ELSE json_build_array(json_data) END AS val FROM pgrst_payload) INSERT INTO "api_x"."api_fruits"("fruit_id", "name") SELECT "fruit_id", "name" FROM json_populate_recordset (null::"api_x"."api_fruits", (SELECT val FROM pgrst_body)) _ RETURNING "api_x"."api_fruits".*) SELECT '' AS total_result_set, pg_catalog.count(_postgrest_t) AS page_total, CASE WHEN pg_catalog.count(_postgrest_t) = 1 THEN coalesce((
WITH data AS (SELECT row_to_json(_) AS row FROM pgrst_source AS _ LIMIT 1)
SELECT array_agg(json_data.key || '=eq.' || json_data.value)
FROM data CROSS JOIN json_each_text(data.row) AS json_data
WHERE json_data.key IN ('')
), array[]::text[]) ELSE array[]::text[] END AS header, '' AS body, nullif(current_setting('response.headers', true), '') AS response_headers, nullif(current_setting('response.status', true), '') AS response_status FROM (SELECT * FROM pgrst_source) _postgrest_t
We can't INSERT into "View columns that are not columns of their base relation".
The obvious workaround is to serve fruit_id as a straight column, just an integer. With some post and preprocessing at the nginx level we can hex encode it there (and hex decode incoming ids). I'm wondering if we can do better than that though. For large API operations, re-encoding the JSON will use a lot of memory and CPU time and it seems so unnecessary.
It would have been great to be able to use a custom CREATE CAST to take the incoming hexadecimal strings and turn them back into integers, something like this:
CREATE CAST (json AS hexid) WITH FUNCTION json_to_hexid AS ASSIGNMENT;
But alas custom casts are ignored on CREATE DOMAIN types. And we can't make a true custom column type because our cloud Postgres host (Google Cloud SQL) doesn't allow custom extensions.
It feels like some combination of INSTEAD OF triggers or rules could work. But when using query parameters to filter results using query parameters (e.g. select a fruit by id), I don't think there's an appropriate trigger to use. INSTEAD OF doesn't work for straight SELECT does it?
For example I've tested doing something like this to take care of INSERT and allow POST with PostgREST. It works:
CREATE OR REPLACE FUNCTION api_fruits_insert()
RETURNS trigger AS
$$
BEGIN
INSERT INTO fruits(fruit_id, name) VALUES (('x' || lpad(NEW.fruit_id, 16, '0'))::bit(64)::bigint::hexid, NEW.name);
RETURN NEW;
END
$$ LANGUAGE 'plpgsql';
CREATE TRIGGER api_fruits_insert
INSTEAD OF INSERT
ON api_fruits
FOR EACH ROW
EXECUTE PROCEDURE api_fruits_insert();
The trouble is in the WHERE clause. Let's PATCH api_fruits?fruit_id=in.(7b,caf3) with {"name": "pear"}. This works out of the box since the name column is updatable but look at the query:
WITH pgrst_source AS (WITH pgrst_payload AS (SELECT $1::json AS json_data), pgrst_body AS ( SELECT CASE WHEN json_typeof(json_data) = 'array' THEN json_data ELSE json_build_array(json_data) END AS val FROM pgrst_payload) UPDATE "api_x"."api_fruits" SET "name" = _."name" FROM (SELECT * FROM json_populate_recordset (null::"api_x"."api_fruits" , (SELECT val FROM pgrst_body) )) _ WHERE "api_x"."api_fruits"."fruit_id" = ANY ($2) RETURNING 1) SELECT '' AS total_result_set, pg_catalog.count(_postgrest_t) AS page_total, array[]::text[] AS header, '' AS body, nullif(current_setting('response.headers', true), '') AS response_headers, nullif(current_setting('response.status', true), '') AS response_status FROM (SELECT * FROM pgrst_source) _postgrest_t
DETAIL: parameters: $1 = '{
"name": "pear"
}', $2 = '{7b,caf3}'
So we have essentially UPDATE api_fruits SET name='berry' WHERE fruit_id IN ('7b', 'caf3');. Surprisingly this works but it's a full table scan so Postgres can evaluate to_hex(fruit_id) for each row looking for matches. The same happens if we try to GET a record by fruit_id. How would we rewrite the WHERE clauses?
It really feels like some combination of just the right Postgres and PostgREST features should be able to get us to a point where it's all happening in Postgres without nginx's help and without excessive complexity. Any ideas?
I am trying to manipulate string data in a column such as if the given string is '20591;#e123456;#17507;#c567890;#15518;#e135791' or '26169;#c785643', then the
result should be like 'e123456;c567890;e135791' or 'c785643'. The number of digits in between can be of any length.
Some of the things I have tried so far are:
select replace('20591;#e123456;#17507;#c567890;#15518;#e135791','#','');
This leaves me with '20591;e123456;17507;c567890;15518;e135791', which still includes the digits without 'e' or 'c' prefixed to them. i want to get rid of 20591, 17507 and 15518.
Create function that will keep a pattern of '%[#][ec][0-9][;]%' and will get rid of the rest.
The most important advise is: Do not store any data in a delimited string. This is violating the most basic principle of relational database concepts (1.NF).
The second hint is SO-related: Please always add / tag your questions with the appropriate tool. The tag [tsql] points to SQL-Server, but this might be wrong (which would invalidate both answers). Please tag the full product with its version (e.g. [sql-server-2012]). Especially with string splitting there are very important product related changes from version to version.
Now to your question.
Working with (almost) any version of SQL-Server
My suggestion uses a trick with XML:
(credits to Alan Burstein for the mockup)
DECLARE #table TABLE (someid INT IDENTITY, somestring VARCHAR(50));
INSERT #table VALUES ('20591;#e123456;#17507;#c567890;#15518;#e135791'),('26169;#c785643')
--the query
SELECT t.someid,t.somestring,A.CastedToXml
,STUFF(REPLACE(A.CastedToXml.query('/x[contains(text()[1],"#") and empty(substring(text()[1],2,100) cast as xs:int?)]')
.value('.','nvarchar(max)'),'#',';'),1,1,'') TheNewList
FROM #table t
CROSS APPLY(SELECT CAST('<x>' + REPLACE(t.somestring,';','</x><x>') + '</x>' AS XML)) A(CastedToXml);
The idea in short:
By replacing the ; with XML tags </x><x> we can transform your delimited list to XML. I included the intermediate XML into the result set. Just click it to see how this works.
In the next query I use a XQuery predicate first to find entries, which contain a # and second, which do NOT cast to an integer without the #.
The thrid step is specific to XML again. The XPath . in .value() will return all content as one string.
Finally we have to replace the # with ; and cut away the leading ; using STUFF().
UPDATE The same idea, but a bit shorter:
You can try this as well
SELECT t.someid,t.somestring,A.CastedToXml
,REPLACE(A.CastedToXml.query('data(/x[empty(. cast as xs:int?)])')
.value('.','nvarchar(max)'),' ',';') TheNewList
FROM #table t
CROSS APPLY(SELECT CAST('<x>' + REPLACE(t.somestring,';#','</x><x>') + '</x>' AS XML)) A(CastedToXml);
Here I use ;# to split your string and data() to implicitly concatenate your values (blank-separated).
UPDATE 2 for v2017
If you have v2017+ I'd suggest a combination of a JSON splitter and STRING_AGG():
SELECT t.someid,STRING_AGG(A.[value],';') AS TheNewList
FROM #table t
CROSS APPLY OPENJSON(CONCAT('["',REPLACE(t.somestring,';#','","'),'"]')) A
WHERE TRY_CAST(A.[value] AS INT) IS NULL
GROUP BY t.someid;
You did not include the version of SQL Server you are on. If you are using 2016+ you can use SPLIT_STRING, otherwise a good T-SQL splitter will do.
Against a single variable:
DECLARE #somestring VARCHAR(1000) = '20591;#e123456;#17507;#c567890;#15518;#e135791';
SELECT NewString = STUFF((
SELECT ','+split.item
FROM STRING_SPLIT(#somestring,';') AS s
CROSS APPLY (VALUES(REPLACE(s.[value],'#',''))) AS split(item)
WHERE split.item LIKE '[a-z][0-9]%'
FOR XML PATH('')),1,1,'');
Against a table:
NewString
----------------------
e123456,c567890,e135791
-- Against a table
DECLARE #table TABLE (someid INT IDENTITY, somestring VARCHAR(50));
INSERT #table VALUES ('20591;#e123456;#17507;#c567890;#15518;#e135791'),('26169;#c785643')
SELECT t.*, fn.NewString
FROM #table AS t
CROSS APPLY
(
SELECT NewString = STUFF((
SELECT ','+split.item
FROM STRING_SPLIT(t.somestring,';') AS s
CROSS APPLY (VALUES(REPLACE(s.[value],'#',''))) AS split(item)
WHERE split.item LIKE '[a-z][0-9]%'
FOR XML PATH('')),1,1,'')
) AS fn;
Returns:
someid somestring NewString
----------- -------------------------------------------------- -----------------------------
1 20591;#e123456;#17507;#c567890;#15518;#e135791 e123456,c567890,e135791
2 26169;#c785643 c785643
I have this query:
some_id = 1
cursor.execute('
SELECT "Indicator"."indicator"
FROM "Indicator"
WHERE "Indicator"."some_id" = %s;', some_id)
I get the following error:
TypeError: 'int' object does not support indexing
some_id is an int but I'd like to select indicators that have some_id = 1 (or whatever # I decide to put in the variable).
cursor.execute('
SELECT "Indicator"."indicator"
FROM "Indicator"
WHERE "Indicator"."some_id" = %s;', [some_id])
This turns the some_id parameter into a list, which is indexable. Assuming your method works like i think it does, this should work.
The error is happening because somewhere in that method, it is probably trying to iterate over that input, or index directly into it. Possibly like this: some_id[0]
By making it a list (or iterable), you allow it to index into the first element like that.
You could also make it into a tuple by doing this: (some_id,) which has the advantage of being immutable.
You should pass query parameters to execute() as a tuple (an iterable, strictly speaking), (some_id,) instead of some_id:
cursor.execute('
SELECT "Indicator"."indicator"
FROM "Indicator"
WHERE "Indicator"."some_id" = %s;', (some_id,))
Your id needs to be some sort of iterable for mogrify to understand the input, here's the relevant quote from the frequently asked questions documentation:
>>> cur.execute("INSERT INTO foo VALUES (%s)", "bar") # WRONG
>>> cur.execute("INSERT INTO foo VALUES (%s)", ("bar")) # WRONG
>>> cur.execute("INSERT INTO foo VALUES (%s)", ("bar",)) # correct
>>> cur.execute("INSERT INTO foo VALUES (%s)", ["bar"]) # correct
This should work:
some_id = 1
cursor.execute('
SELECT "Indicator"."indicator"
FROM "Indicator"
WHERE "Indicator"."some_id" = %s;', (some_id, ))
Slightly similar error when using Django:
TypeError: 'RelatedManager' object does not support indexing
This doesn't work
mystery_obj[0].id
This works:
mystery_obj.all()[0].id
Basically, the error reads Some type xyz doesn't have an __ iter __ or __next__ or next function, so it's not next(), or itsnot[indexable], or iter(itsnot), in this case the arguments to cursor.execute would need to implement iteration, most commonly a List, Tuple, or less commonly an Array, or some custom iterator implementation.
In this specific case the error happens when the classic string interpolation goes to fill the %s, %d, %b string formatters.
Related:
How to implement __iter__(self) for a container object (Python)
Pass parameter into a list, which is indexable.
cur.execute("select * from tableA where id =%s",[parameter])
I had the same problem and it worked when I used normal formatting.
cursor.execute(f'
SELECT "Indicator"."indicator"
FROM "Indicator"
WHERE "Indicator"."some_id" ={some_id};')
Typecasting some_id to string also works.
cursor.execute(""" SELECT * FROM posts WHERE id = %s """, (str(id), ))
I have the following case statement to prepare as a dynamic as shown below:
Example:
I have the case statement:
case cola
when cola between '2001-01-01' and '2001-01-05' then 'G1'
when cola between '2001-01-10' and '2001-01-15' then 'G2'
when cola between '2001-01-20' and '2001-01-25' then 'G3'
when cola between '2001-02-01' and '2001-02-05' then 'G4'
when cola between '2001-02-10' and '2001-02-15' then 'G5'
else ''
end
Note: Now I want to create dynamic case statement because of the values dates and name passing as a parameter and it may change.
Declare
dates varchar = '2001-01-01to2001-01-05,2001-01-10to2001-01-15,
2001-01-20to2001-01-25,2001-02-01to2001-02-05,
2001-02-10to2001-02-15';
names varchar = 'G1,G2,G3,G4,G5';
The values in the variables may change as per the requirements, it will be dynamic. So the case statement should be dynamic without using loop.
You may not need any function for this, just join to a mapping data-set:
with cola_map(low, high, value) as (
values(date '2001-01-01', date '2001-01-05', 'G1'),
('2001-01-10', '2001-01-15', 'G2'),
('2001-01-20', '2001-01-25', 'G3'),
('2001-02-01', '2001-02-05', 'G4'),
('2001-02-10', '2001-02-15', 'G5')
-- you can include as many rows, as you want
)
select table_name.*,
coalesce(cola_map.value, '') -- else branch from case expression
from table_name
left join cola_map on table_name.cola between cola_map.low and cola_map.high
If your date ranges could collide, you can use DISTINCT ON or GROUP BY to avoid row duplication.
Note: you can use a simple sub-select too, I used a CTE, because it's more readable.
Edit: passing these data (as a single parameter) can be achieved by passing a multi-dimensional array (or an array of row-values, but that requires you to have a distinct, predefined composite type).
Passing arrays as parameters can depend on the actual client (& driver) you use, but in general, you can use the array's input representation:
-- sql
with cola_map(low, high, value) as (
select d[1]::date, d[2]::date, d[3]
from unnest(?::text[][]) d
)
select table_name.*,
coalesce(cola_map.value, '') -- else branch from case expression
from table_name
left join cola_map on table_name.cola between cola_map.low and cola_map.high
// client pseudo code
query = db.prepare(sql);
query.bind(1, "{{2001-01-10,2001-01-15,G2},{2001-01-20,2001-01-25,G3}}");
query.execute();
Passing each chunk of data separately is also possible with some clients (or with some abstractions), but this is highly depends on your driver/orm/etc. you use.
I must to write a UDF returning a Table. I’ve done it with Static SQL.
I’ve created Procedures preparing a Dynamic and Complex SQL sentence and returning a cursor.
But now I must to create a UDF with Dynamic SQL and return a table to be used with an IN clause inside other select.
It is possible on DB2 v5R4? Do you have an example?
Thanks in advance...
I don't have V5R4, but I have i 6.1 and V5R3. I have a 6.1 example, and I poked around in V5R3 to find how to make the same example work there. I can't guarantee V5R4, but this ought to be extremely close. Generating the working V5R3 code into 'Run SQL Scripts' gives this:
DROP SPECIFIC FUNCTION SQLEXAMPLE.DYNTABLE ;
SET PATH "QSYS","QSYS2","SYSPROC","SYSIBMADM","SQLEXAMPLE" ;
CREATE FUNCTION SQLEXAMPLE.DYNTABLE (
SELECTBY VARCHAR( 64 ) )
RETURNS TABLE (
CUSTNBR DECIMAL( 6, 0 ) ,
CUSTFULLNAME VARCHAR( 12 ) ,
CUSTBALDUE DECIMAL( 6, 0 ) )
LANGUAGE SQL
NO EXTERNAL ACTION
MODIFIES SQL DATA
NOT FENCED
DISALLOW PARALLEL
CARDINALITY 100
BEGIN
DECLARE DYNSTMT VARCHAR ( 512 ) ;
DECLARE GLOBAL TEMPORARY TABLE SESSION.TCUSTCDT
( CUSTNBR DECIMAL ( 6 , 0 ) NOT NULL ,
CUSTNAME VARCHAR ( 12 ) ,
CUSTBALDUE DECIMAL ( 6 , 2 ) )
WITH REPLACE ;
SET DYNSTMT = 'INSERT INTO Session.TCustCDt SELECT t2.CUSNUM , (t2.INIT CONCAT '' '' CONCAT t2.LSTNAM) as FullName , t2.BALDUE FROM QIWS.QCUSTCDT t2 ' CONCAT CASE WHEN SELECTBY = '' THEN '' ELSE SELECTBY END ;
EXECUTE IMMEDIATE DYNSTMT ;
RETURN SELECT * FROM SESSION . TCUSTCDT ;
END ;
COMMENT ON SPECIFIC FUNCTION SQLEXAMPLE.DYNTABLE
IS 'UDTF returning dynamic table' ;
And in 'Run SQL Scripts', the function can be called like this:
SELECT t1.* FROM TABLE(sqlexample.dyntable('WHERE STATE = ''TX''')) t1
The example is intended to work over IBM's sample QCUSCDT table in library QIWS. Most systems will have that table available. The table function returns values from two QCUSCDT columns, CUSNUM and BALDUE, directly through two of the table function's columns, CUSTNBR and CUSTBALDUE. The third table function column, CUSTFULLNAME, gets its value by a concatenation of INIT and LSTNAM from QCUSTCDT.
However, the part that apparently relates to the question is the SELECTBY parameter of the function. The usage example shows that a WHERE clause is passed in and used to help built a dynamic 'INSERT INTO... SELECT...statement. The example shows that rows containingSTATE='TX'` will be returned. A more complex clause could be passed in or the needed condition(s) could be retrieved from somewhere else, e.g., from another table.
The dynamic statement inserts rows into a GLOBAL TEMPORARY TABLE named SESSION.TCUSTCDT. The temporary table is defined in the function. The temporary column definitions are guaranteed (by the developer) to match the 'RETURNS TABLE` columns of the table function because no dynamic changes can be made to any of those elements. This allows SQL to handle reliably columns returned from the function, and that lets it compile the function.
The RETURN statement simply returns whatever rows are in the temporary table after the dynamic statement completes.
The various field definitions take into account the somewhat unusual definitions in the QCUSTCDT file. Those don't make great sense, but they're useful enough.