I have a table as:
CREATE TABLE tbl_temp (id serial, friend_id int, name varchar(32));
I wish I could run the following SQL:
PREPARE x AS SELECT {$1,friend_id} FROM tbl_temp WHERE id = ANY($2);
EXECUTE x(33, ARRAY[1,2,3,4])
I basically looking for a statement that will return me an array of two ints first of which will be user input and second will be from table column like friend_id.
Is it really possible in PostgreSQL?
The results from SELECT ($1, friend_id) FROM tbl_temp;
EXECUTE x(44);
row
--------
(44,1)
(44,2)
(44,3)
(3 rows)
If I use PQgetvalue(PGres, 0, 0) how will the result look like: {44,45} or like (44,45)?
I think you want to use the array constructor syntax:
SELECT ARRAY[$1, friend_id] FROM tbl_temp WHERE id = ANY($2)
i'm not sure i understand what you want...
to return an array, do this.
SELECT (44, "friend_id") FROM "tbl_temp" WHERE id = ANY(ARRAY[1,2,3,4]);
Related
I'm passing a parameter like '1,2,3' to this statement:
SELECT *
FROM Negative
WHERE IdNegative IN (#IdNegative)
But I want to return all records (like the records with an id 1,2,3,4,5,6...) when the parameter is empty. Is there a way to do this?
Thank you.
Parameters and variables are not simply pasted into the query by the compiler. They are inserted as actual compiled values, so in this case the string 1,2,3 is never going to be equal to any of the numbers 1 2 3.
You need to declare as a table variable or as a Table-Valued Parameter
DECLARE #IdNegative TABLE (id int PRIMARY KEY);
INSERT #IdNegative VALUES (1),(2),(3);
SELECT *
FROM Negative
WHERE IdNegative IN (SELECT id FROM #IdNegative);
I am working on a sql database which will provide with data some grid. The grid will enable filtering, sorting and paging but also there is a strict requirement that users can enter free text to a text input above the grid for example
'Engine 1001 Requi' and that the result will contain only rows which in some columns contain all the pieces of the text. So one column may contain Engine, other column may contain 1001 and some other will contain Requi.
I created a technical column (let's call it myTechnicalColumn) in the table (let's call it myTable) which will be updated each time someone inserts or updates a row and it will contain all the values of all the columns combined and separated with space.
Now to use it with entity framework I decided to use a table valued function which accepts one parameter #searchQuery and it will handle it like this:
CREATE FUNCTION myFunctionName(#searchText NVARCHAR(MAX))
RETURNS #Result TABLE
( ... here come columns )
AS
BEGIN
DECLARE #searchToken TokenType
INSERT INTO #searchToken(token) SELECT value FROM STRING_SPLIT(#searchText,' ')
DECLARE #searchTextLength INT
SET #searchTextLength = (SELECT COUNT(*) FROM #searchToken)
INSERT INTO #Result
SELECT
... here come columns
FROM myTable
WHERE (SELECT COUNT(*) FROM #searchToken WHERE CHARINDEX(token, myTechnicalColumn) > 0) = #searchTextLength
RETURN;
END
Of course the solution works fine but it's kinda slow. Any hints how to improve its efficiency?
You can use an inline Table Valued Function, which should be quite a lot faster.
This would be a direct translation of your current code
CREATE FUNCTION myFunctionName(#searchText NVARCHAR(MAX))
RETURNS TABLE
AS RETURN
(
WITH searchText AS (
SELECT value token
FROM STRING_SPLIT(#searchText,' ') s(token)
)
SELECT
... here come columns
FROM myTable t
WHERE (
SELECT COUNT(*)
FROM searchText
WHERE CHARINDEX(s.token, t.myTechnicalColumn) > 0
) = (SELECT COUNT(*) FROM searchText)
);
GO
You are using a form of query called Relational Division Without Remainder and there are other ways to cut this cake:
CREATE FUNCTION myFunctionName(#searchText NVARCHAR(MAX))
RETURNS TABLE
AS RETURN
(
WITH searchText AS (
SELECT value token
FROM STRING_SPLIT(#searchText,' ') s(token)
)
SELECT
... here come columns
FROM myTable t
WHERE NOT EXISTS (
SELECT 1
FROM searchText
WHERE CHARINDEX(s.token, t.myTechnicalColumn) = 0
)
);
GO
This may be faster or slower depending on a number of factors, you need to test.
Since there is no data to test, i am not sure if the following will solve your issue:
-- Replace the last INSERT portion
INSERT INTO #Result
SELECT
... here come columns
FROM myTable T
JOIN #searchToken S ON CHARINDEX(S.token, T.myTechnicalColumn) > 0
This may be a very basic question, but I have been struggling with this.
I have a SSMS query that I'll be using multiple times for a large set of client Ids. Its quite cumbersome to have to amend the parameters in all the where clauses every time I want to run it.
For simplicity, I want to convert a query like the one below:
SELECT
ID,
Description
From TestDb
Where ID in ('1-234908','1-345678','1-12345')
to a query of the format below so that I only need to change my variable field once and it can be applied across my query:
USE TestDb
DECLARE #ixns NVARCHAR(100)
SET #ixns = '''1-234908'',''1-345678'',''1-12345'''
SELECT
ID,
Description
From TestDb
Where ID IN #ixns
However, the above format doesn't work. Can anyone help me on how I can use a varchar/string variable in my "where" clause for my query so that I can query multiple IDs at the same time and only have to adjust/set my variable once?
Thanks in advance :D
The most appropriate solution would be to use a table variable:
DECLARE #ixns TABLE (id NVARCHAR(100));
INSERT INTO #ixns(id) VALUES
('1-234908'),
('1-345678'),
('1-12345');
SELECT ID, Description
FROM TestDb
WHERE ID IN (SELECT id FROM #ixns);
You can load ids to temp table use that in where condition
USE TestDb
DECLARE #tmpIDs TABLE
(
id VARCHAR(50)
)
insert into #tmpIDs values ('1-234908')
insert into #tmpIDs values ('1-345678')
insert into #tmpIDs values ('1-12345')
SELECT
ID,
Description
From TestDb
Where ID IN (select id from #tmpIDs)
The most appropriate way is to create a table type because it is possible to pass this type as parameters.
1) Creating the table type with the ID column.
create type MyListID as table
(
Id int not null
)
go
2) Creating the procedure that receives this type as a parameter.
create procedure MyProcedure
(
#MyListID as MyListID readonly
)
as
select
column1,
column2
...
from
MyTable
where
Id in (select Id from #MyListID)
3) In this example you can see how to fill this type through your application ..: https://stackoverflow.com/a/25871046/8286724
I'm new to firebird and I have verious issues. I want to insert various lines into a table selected from another table.
Here's the code:
/*CREATE GENERATOR POS; */
SET GENERATOR POS TO 1;
SET TERM ^;
create trigger BAS_pkassign
for MATERIAL
active before insert position 66
EXECUTE BLOCK
AS
declare posid bigint;
select gen_id(POS, 1)
from RDB$DATABASE
into :posid;
BEGIN
END
SET TERM ; ^
INSERT INTO MATERIAL ( /*ID */ LOCATION, POSID, ARTID, ARTIDCONT, QUANTITY )
SELECT 1000, ':posid', 309, BAS_ART.ID, 1
FROM BAS_ART
WHERE BAS_ART.ARTCATEGORY LIKE '%MyWord%'
The ID should autoincrement from 66 on. The posid should autoincrement from 1 on.
Actually it is not inserting anything.
I'm using Firebird Maestro and have just opened the SQL Script Editor (which doesnt throw any error message on executing the script).
Can anybody help me?
Thanks!
Additional information:
The trigger should autoincrement the column "ID" - but I dont know how exactly I can change it so it works.. The ':posid' throws an error using it :posid but like this theres no error (I guess its interpretated as a string). But how do I use it right?
I dont get errors when I execute it. The table structure is easy. I have 2 tables:
1.
Material (
ID (INTEGER),
Location (INTEGER),
POSID (INTEGER),
ARTID (INTEGER),
ARTIDCONT (INTEGER),
QUANTITY (INTEGER),
OTHERCOLUMN (INTEGER))
and the 2. other table
BAS_ART (ID (INTEGER), ARTCATEGORY (VARCHAR255))
-> I want to insert all entries from the table BAS_ART which contain "MyWord" in the column ARTCATEGORY into the MATERIAL table.
I don't understand why you need the trigger at all.
This problem:
I want to insert all entries from the table BAS_ART which contain "MyWord" into the MATERIAL table
Can be solved with a single insert ... select statement.
insert into material (id, location, posid, artid, quantity)
select next value for seq_mat_id, 1000, next value for seq_pos, id, 1
from bas_art
where artcategory = 'My Word';
This assumes that there is a second sequence (aka "generator") that is named seq_mat_id that provides the new id for the column material.id
For most of my answer I will assume a very simple table:
CREATE TABLE MyTable (
ID BIGINT PRIMARY KEY,
SomeValue VARCHAR(255),
posid INTEGER
)
Auto-increment identifier
Firebird (up to version 2.5) does not have an identity column type (this will be added in Firebird 3), instead you need to use a sequence (aka generator) and a trigger to get this.
Sequence
First you need to create a sequence using CREATE SEQUENCE:
CREATE SEQUENCE seqMyTable
A sequence is atomic which means interleaving transactions/connections will not get duplicate values, it is also outside transaction control, which means that a ROLLBACK will not revert to the previous value. In most uses a sequences should always increase, so the value reset you do at the start of your question is wrong for almost all purposes; for example another connection could reset the sequence as well midway in your execution leaving you with unintended duplicates of POSID.
Trigger
To generate a value for an auto-increment identifier, you need to use a BEFORE INSERT TRIGGER that assigns a generated value to the - in this example - ID column.
CREATE TRIGGER trgMyTableAutoIncrement FOR MyTable
ACTIVE BEFORE INSERT POSITION 0
AS
BEGIN
NEW.ID = NEXT VALUE FOR seqMyTable;
END
In this example I always assign a generated value, other examples assign a generated value only when the ID is NULL.
Getting the value
To get the generated value you can use the RETURNING-clause of the INSERT-statement:
INSERT INTO MyTable (SomeValue) VALUES ('abc') RETURNING ID
INSERT INTO ... SELECT
Using INSERT INTO ... SELECT you can select rows from one table and insert them into others. The reason it doesn't work for you is because you are trying to assign the string value ':pos' to a column of type INTEGER, and that is not allowed.
Assuming I have another table MyOtherTable with a similar structure as MyTable I can transfer values using:
INSERT INTO MyTable (SomeValue)
SELECT SomeOtherValue
FROM MyOtherTable
Using INSERT INTO ... SELECT it is not possible to obtain the generated values unless only a single row was inserted.
Guesswork with regard to POSID
It is not clear to me what POSID is supposed to be, and what values it should have. It looks like you want to have an increasing value starting at 1 for a single INSERT INTO ... SELECT. In versions of Firebird up to 2.5 that is not possible in this way (in Firebird 3 you would be able to use ROW_NUMBER() for this).
If my guess is right, then you will need to use an EXECUTE BLOCK (or a stored procedure) to assign and increase the value for every row to be inserted.
The execute block would be something like:
EXECUTE BLOCK
AS
DECLARE posid INTEGER = 1;
DECLARE someothervalue VARCHAR(255);
BEGIN
FOR SELECT SomeOtherValue FROM MyOtherTable INTO :someothervalue DO
BEGIN
INSERT INTO MyTable (SomeValue, posid) VALUES (:someothervalue, :posid);
posid = posid + 1;
END
END
Without an ORDER BY with the SELECT the value of posid is essentially meaningless, because there is no guaranteed order.
Is there a way to combine assigning a value to a variable and Selecting a column in sql. I need to compute and select a column in a table based on the variable. The variable's value changes based on another column in the table.
var #BeginValue
Columns in table : ReducedBy
My initial begin value is stored in #BeginValue. The table has reducedBy which is a factor by which my begin value should be reduced. So when i select, beginvalue for the first recored would be #BeginValue and the #EndValue should be #BeginValue = #BeginValue - reducedBy. It continues like this, as many times as the number of records in my table.
Result set must be like this:
#Begin = 10
Begin End ReducedBy
10 8 2
8 6 2
6 5 1
Is there a way with which i can achieve this without using a cursor or with multiple update statements.
You can't assign in a query that returns a result set. The closest you can get is to store the result in a table variable. Then you can both do computations against that table, and return it as a result set:
-- Store results in table variable
declare #tbl table (id int, col1 int, ...)
insert #tbl
(id, col1, ...)
select id
, col1
, ...
from ... your query here ...
-- Assign variable
select #YourVariable = ... your computation here ...
from #tbl
-- Return result set
select *
from #tbl
If your question is
Can I do..
SELECT #a = field, field2 from table
and get a resultset and set the value of #a?
Then the answer is no, not in a single statement.