I'm using PostgreSQL 9.1 and let's say I have a type in PostgreSQL like:
CREATE TYPE sticker AS (
customer_id integer,
customer_machine_id integer,
);
and I have a plpgsql named get_sticker that returns the type sticker...
I can do this fine:
select get_sticker(a_value), * from foo_bar;
But, this returns the result in a tuple (which totally makes sense). But, how can I convert (basically unpack) to columns?
It seems like it would be something like the following, but it fails.
select get_sticker(a_value).*, * from foo_bar; -- <<<< FAIL
Error message:
ERROR: syntax error at or near "."
SQL state: 42601
You need an extra set of parentheses:
select (get_sticker(a_value)).*, * from foo_bar;
Related
Why these SQLs can't work in PostgreSQL?
SELECT * FROM (t as a);
or
SELECT * FROM (t);
ERROR: syntax error at or near ")"
Those SQLs work well in MySQL.
Well, it's invalid SQL.
If you want to give the table an alias you need to use from t as a.
The form from (....) requires a valid query inside the parentheses and t as a (or just t) is not a valid query. Additionally: a derived table (which is what (...) defines) requires an alias. So at least it has to be from (...) as bla
To get all rows and all columns from a table the SQL standard provides the shortcut table some_table which is supported by Postgres.
So the following would be valid:
select * from (table t) as a
Typically, table alias' are applied where there is a join. For example:
SELECT alias1.login_name, alias2.name
FROM tablename1 AS alias1
JOIN tablename2 AS alias2
ON alias1.id = alias2.role_id;
To apply an alias to a single table:
SELECT * FROM tablename AS alias;
..will do it for you, no need for parentheses.
You can confirm/test by example below if value is an integer:
SELECT * FROM tablename AS alias
WHERE alias.colum = value;
..or if value is a string:
SELECT * FROM tablename AS alias
WHERE alias.colum = 'value';
postgreSQL is strongly-typed, so the first example above will work for Int and Bool values, however if you have Date or other values, you may need to apply type casting. See this link for helpful info*: www.postgresqltutorial.com/postgresql-tutorial/postgresql-cast.
**Remember: For psql strings, always use single quotes for values, use double quotes for table names and column names.
I created two functions. The first function, getProductOrder, is getting token whose type is character varying. The second function is getOrderTechnicalDetails whose function parameter is character varying.
For example When I call getProductOrder with quotation marks that is working nothing problem the function
Worked example
select
(select row_to_json(getOrderTechnicalDetails('991964b80d4f41a416b48ac99bdc07ad')) as techDetails),
o.*
from
(select * from getProductOrder(null, '54e91016-46d0-11e7-912d-001dd8b72237', null, 9181, 1::smallint)) o
But I have to use dynamic parameter here problem is casting problem function can't determine casting.
When I execute this query I get syntax error. How can I solve this problem?
Query
select
(select row_to_json(getOrderTechnicalDetails(o.token::character varying)) as techDetails),
o.*
from
(select * from getProductOrder(null, '54e6341-46d0-11e7-912d-001dd8b72237', null, 9181, 1::smallint)) o
Error
ERROR: invalid input syntax for integer: "-"
SQL state: 22P02
Context: SQL function "getordertechnicaldetails" statement 1
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.
I have a table with a varchar column, and I want to find values that match a certain number. So lets say that column contains the following entries (except with millions of rows in real life):
123456789012
2345678
3456
23 45
713?2
00123456789012
So I decide I want all the rows which are numerically 123456789012 write a statement that looks something like this:
SELECT * FROM MyTable WHERE CAST(MyColumn as bigint) = 123456789012
It should return the first and last row, but instead the whole query blows up because it can't convert the "23 45" and "713?2" to bigint.
Is there another way to do the conversion that will return NULL for values that can't convert?
SQL Server does NOT guarantee boolean operator short-circuit, see On SQL Server boolean operator short-circuit. So all solution using ISNUMERIC(...) AND CAST(...) are fundamentally flawed (they may work, but hey can arbitrarily fail later dependiong on the generated plan). A better solution is using CASE, as Thomas suggests: CASE ISNUMERIC(...) WHEN 1 THEN CAST(...) ELSE NULL END. But, as gbn pointed out, ISNUMERIC is notoriously finicky in identifying what 'numeric' means and many cases where one would expect it to return 0 it returns 1. So mixing the CASE with the LIKE:
CASE WHEN MyRow NOT LIKE '%[^0-9]%' THEN CAST(MyRow as bigint) ELSE NULL END
But the real problem is that if you have millions of rows and you have to search them like this, you'll always end up scanning end-to-end since the expression is not SARG-able (no matter how we rewrite it). The real issue here is data purity, and should be addressed at the appropriate level, where the data is populated. Another thing to consider is if is possible to create a persisted computed column with this expression and create a filtered index on it which eliminates NULL (ie. non-numeric). That would speed up things a little.
If you are using SQL Server 2012 you can use the 2 new methods:
TRY_CAST()
TRY_CONVERT()
Both methods are equivalent. They return a value cast to the specified data type if the cast succeeds; otherwise, returns null. The only difference is that CONVERT is SQL Server specific, CAST is ANSI. using CAST will make your code more portable (although not sure if any other database provider implements TRY_CAST)
ISNUMERIC will accept empty string and values like 1.23 or 5E-04 so could be unreliable.
And you don't know what order things will be evaluated in so it could still fail (SQL is declarative, not procedural, so the WHERE clause probably won't be evaluated left to right)
So:
you want to accept value that consist only of the characters 0-9
you need to materialise the "number" filter so it's applied before CAST
Something like:
SELECT
*
FROM
(
SELECT TOP 2000000000 *
FROM MyTable
WHERE MyColumn NOT LIKE '%[^0-9]%' --double negative rejects anything except 0-9
ORDER BY MyColumn
) foo
WHERE
CAST(MyColumn as bigint) = 123456789012 --applied after number check
Edit: quick example that fails.
CREATE TABLE #foo (bigintstring varchar(100))
INSERT #foo (bigintstring )VALUES ('1.23')
INSERT #foo (bigintstring )VALUES ('1 23')
INSERT #foo (bigintstring )VALUES ('123')
SELECT * FROM #foo
WHERE
ISNUMERIC(bigintstring) = 1
AND
CAST(bigintstring AS bigint) = 123
SELECT *
FROM MyTable
WHERE ISNUMERIC(MyRow) = 1
AND CAST(MyRow as float) = 123456789012
The ISNUMERIC() function should give you what you need.
SELECT * FROM MyTable
WHERE ISNUMERIC(MyRow) = 1
AND CAST(MyRow as bigint) = 123456789012
And to add a case statement like Thomas suggested:
SELECT * FROM MyTable
WHERE CASE(ISNUMERIC(MyRow)
WHEN 1 THEN CAST(MyRow as bigint)
ELSE NULL
END = 123456789012
http://msdn.microsoft.com/en-us/library/ms186272.aspx
SELECT *
FROM MyTable
WHERE (ISNUMERIC(MyColumn) = 1) AND (CAST(MyColumn as bigint) = 123456789012)
Additionally you can use a CASE statement in order to get null values.
SELECT
CASE
WHEN (ISNUMERIC(MyColumn) = 1) THEN CAST(MyColumn as bigint)
ELSE NULL
END AS 'MyColumnAsBigInt'
FROM tableName
If you require additional filtering, for numerics which are not valid to be cast to bigint, you can use the following instead of ISNUMERIC:
PATINDEX('%[^0-9]%',MyColumn)) = 0
If you need decimal values instead of integers, cast to float instead and change the regex to '%[^0-9.]%'
I have a query in postgres
insert into c_d (select * from cd where ak = '22019763');
And I get the following error
ERROR: column "region" is of type integer but expression is of type character varying
HINT: You will need to rewrite or cast the expression.
An INSERT INTO table1 SELECT * FROM table2 depends entirely on order of the columns, which is part of the table definition. It will line each column of table1 up with the column of table2 with the same order value, regardless of names.
The problem you have here is whatever column from cd with the same order value as c_d of the table "region" has an incompatible type, and an implicit typecast is not available to clear the confusion.
INSERT INTO SELECT * statements are stylistically bad form unless the two tables are defined, and will forever be defined, exactly the same way. All it takes is for a single extra column to get added to cd, and you'll start getting errors about extraneous extra columns.
If it is at all possible, what I would suggest is explicitly calling out the columns within the SELECT statement. You can call a function to change type within each of the column references (or you could define a new type cast to do this implicitly -- see CREATE CAST), and you can use AS to set the column label to match that of your target column.
If you can't do this for some reason, indicate that in your question.
Check out the PostgreSQL insert documentation. The syntax is:
INSERT INTO table [ ( column [, ...] ) ]
{ DEFAULT VALUES | VALUES ( { expression | DEFAULT } [, ...] ) | query }
which here would look something like:
INSERT INTO c_d (column1, column2...) select * from cd where ak = '22019763'
This is the syntax you want to use when inserting values from one table to another where the column types and order are not exactly the same.