Yet another stored procedure syntax error - IF-THEN-ELSE - postgresql

Using postgresql 8.4, I'm trying to write a function, and it looks like this:
CREATE OR REPLACE FUNCTION addorupdate( smallint, varchar(7) ) RETURNS void AS
$$
BEGIN
IF EXISTS (SELECT * FROM consist WHERE slave = $1) THEN
UPDATE consist SET
master = $2
where slave = $1;
ELSE
INSERT INTO consist(slave, master) VALUES ( $2, $1 );
END IF;
END;
$$
LANGUAGE SQL;
However, it fails like this:
ERROR: syntax error at or near "IF"
LINE 4: IF EXISTS (SELECT * FROM consist WHERE slave = $1) THEN
...and I've been wasting too much time and caffeine on figuring out why and could use someone with fresh eyes to help me out.
If it's not clear what i'm trying to achieve:
slaves is a column of unique values. If it exists, UPDATE it with the current master. If not, INSERT.
UPDATE:
Changed language to plpgsql, and it now throws:
ERROR: language "plpgsql" does not exist
UPDATE:
CREATE LANGUAGE plpgsql;
(: RESOLVED :)

Your language needs to be plpgsql not sql.

Related

postgresql CONCAT function error when use in a trigger

This might be a stupid question but pardon me, I'm trying to convert one of my MariaDB database into a PostgreSQL database. Here I'm getting an error while executing this function.
I cannot find what's wrong here,
create function tg_prodcut_insert()
returns trigger as '
BEGIN
SET NEW.id = CONCAT(1, LPAD(INSERT INTO product_seq VALUES (NULL) returning id, 6, 0));
END;
' LANGUAGE 'plpgsql';
Error is pointing to the 1 in CONCAT method, The type of id I'm trying to SET is char(7)
EDIT
I also tried this, this won't work either,
create function tg_orders_insert()
returns trigger as '
BEGIN
INSERT INTO order_seq VALUES (NULL);
SET NEW.id = CONCAT('1', LPAD(LAST_INSERT_ID(), 6, 0));
END;
' LANGUAGE 'plpgsql';
Thanks in advance.
It seems you are trying to simulate some kind of sequence with that code by inserting into a table and then getting the auto_increment value from that.
This can be done much more efficiently using a sequence in Postgres.
The error you get also isn't caused by the concat() function but because you are using the wrong syntax.
Value assignment is done using := in PL/pgSQL.
And there is also no last_insert_id() function in Postgres. To get the next value from a sequence use nextval(), to get the most recently generated value, you can use lastval() but that's not necessary here.
create sequence product_id_seq;
create function tg_product_insert()
returns trigger as
$$
BEGIN
NEW.id := concat('ORD', to_char(nextval('product_id_seq'), 'FM00000000'));
return new;
END;
$$
LANGUAGE plpgsql;
you will need to create a before trigger for that to work:
create trigger product_seq_trigger
before insert on product
for each row
execute procedure tg_product_insert();
Online example
But it would be a lot more efficient to switch to a proper identity column instead and get rid of the trigger.

Calling a function for each updated row in postgresql

I have a sql UPDATE statement in a plpgsql function. I now want to call the pg_notify function for each updated row and am uncertain if my solution is the best possibility.
I am not aware of any position in the UPDATE statement itself where I could apply the function. I don't think it is possible in the SET part and if I would apply the function in the WHERE part, it would be applied to each row as it is checked and not only the updated rows, correct?
I therefore thought I could use the RETURNING part for my purposes and designed the function like this:
CREATE OR REPLACE FUNCTION function_name() RETURNS VOID AS $BODY$
BEGIN
UPDATE table1
SET a = TRUE
FROM table2
WHERE table1.b = table2.c
AND <more conditions>
RETURNING pg_notify('notification_name', table1.pk);
END;
$BODY$ LANGUAGE 'plpgsql' VOLATILE;
Unfortunately this gave me an error saying that I am not using or storing the return value of the query anywhere. I therefore tried putting PERFORM in front of the query but this seemed to be syntactically incorrect.
After trying different combinations with PERFORM my ultimate solution is this:
CREATE OR REPLACE FUNCTION function_name() RETURNS VOID AS $BODY$
DECLARE
dev_null INTEGER;
BEGIN
WITH updated AS (
UPDATE table1
SET a = TRUE
FROM table2
WHERE table1.b = table2.c
AND <more conditions>
RETURNING pg_notify('notification_name', table1.pk)
)
SELECT 1 INTO dev_null;
END;
$BODY$ LANGUAGE 'plpgsql' VOLATILE;
This works as it is supposed to, but I feel like there should be a better solution which does not temporarily store a useless result and does not use a useless variable.
Thank you for your help.
** EDIT 1 **
As can be seen in #pnorton 's answer, a trigger would do the trick in most cases. For me, however, it is not applicable as the receiver of the notifications also sometimes updates the table and I do not want to generate notifications in such a case
"I have a sql UPDATE statement in a plpgsql function. I now want to
call the pg_notify function for each updated row "
Ok I might be tempted to use a trigger Eg
CREATE TABLE foobar (id serial primary key, name varchar);
CREATE OR REPLACE FUNCTION notify_trigger() RETURNS trigger AS $$
DECLARE
BEGIN
PERFORM pg_notify('watch_tb_update', TG_TABLE_NAME || ',id,' || NEW.id );
RETURN new;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER foobar_trigger AFTER INSERT ON foobar
FOR EACH ROW EXECUTE PROCEDURE notify_trigger();
LISTEN watch_tb_update;
INSERT into foobar(id, name) values(1,'test_name');
I've tested this and it works fine

Postgres trigger syntax

Using SQLFiddle, PostgreSQL 9.3.1.
I am learning to define triggers in PostgreSQL, and after doing some research I've found out the following:
Triggers in Postgres are different from MYSQL. Where in Postgres you must create a function that RETURNS TRIGGER, in MySQL you can just create a trigger. So this is what I've come up with:
On Employee Insert, we want to update Departments Total Salary.
CREATE FUNCTION update_sal() RETURNS TRIGGER AS $$
BEGIN
IF NEW.dno IS NOT NULL THEN
UPDATE Department SET Total_sal = total_sal + NEW.salary
WHERE department.dno = NEW.dno;
END IF;
RETURN NULL;
END;
$$ Language plpgsql;
CREATE TRIGGER updateInsert
AFTER INSERT ON Employee
FOR EACH ROW
EXECUTE PROCEDURE update_sal();
And I'm getting the following error:
Schema Creation Failed: ERROR: unterminated dollar-quoted string at or near "$$
BEGIN IF NEW.dno IS NOT NULL THEN UPDATE Department
SET Total_sal = total_sal +NEW.salary WHERE department.dno = NEW.dno":
I've solved the issue thanks to Database Function giving an error - Postgresql
It seems just changing the query terminator at the bottom of the Scheme Window solves this issue.
If you copy-pasted the code, then you've got a simple syntax error: ENDl should be END; in the last-but-one line of the function definition.
Otherwise, it looks good to me.

PostgreSQL trigger raises error 55000

after migrating from PostgreSQL server version 9 to 8.4 I have encountered very strange error.
Short description:
If there is a trigger on a given table for each row before insert or update and one uses in conditional statement (if-else) TG_OP value check and OLD object, following error raises when doinng INSERT:
ERROR: record "old" is not assigned yet
DETAIL: The tuple structure of a not-yet-assigned record is indeterminate.
Detailed description:
There is following DB structure:
CREATE TABLE table1
(
id serial NOT NULL,
name character varying(256),
CONSTRAINT table1_pkey PRIMARY KEY (id)
)
WITH (OIDS=FALSE);
CREATE OR REPLACE FUNCTION exemplary_function()
RETURNS trigger AS
$BODY$ BEGIN
IF TG_OP = 'INSERT' OR OLD.name <> NEW.name THEN
NEW.name = 'someName';
END IF;
RETURN NEW;
END;
$BODY$
LANGUAGE plpgsql VOLATILE COST 100;
CREATE TRIGGER trigger1
BEFORE INSERT OR UPDATE
ON table1
FOR EACH ROW EXECUTE PROCEDURE exemplary_function();
and following SQL query that triggers error:
INSERT INTO table1 (name) VALUES ('other name')
It seems like parser is not stopping on TG_OP = 'INSERT' condition (and it should, because it is true) but checks another one and that triggers an error.
What's interesting, I was only able to reproduce it on version 8.4.
Postgres doesn't officially do short cuts on boolean statements (Unlike C for example)
It does say it that sometimes it can decide to short cut (see docs) but it might just easily decide to short cut on the second expression rather than the first.
It basically looks at how complicated the expressions on each side are before deciding the evaluation order. Then if that is TRUE it can decide not to bother with the other side.
In this case, it looks like its trying to interpret OLD while its still trying to decide the best order in which to evaluate the expression.
You should be able get around this by using a CASE to split the expressions eg.
IF (CASE WHEN TG_OP = 'INSERT' THEN TRUE ELSE OLD.name <> NEW.name END) THEN

ERROR: unterminated quoted string at or near

While executing below shown trigger code using ANT I am getting the error
org.postgresql.util.PSQLException: ERROR: unterminated quoted string at or near "' DECLARE timeout integer"
Position: 57
I am able to sucessfully execute the below code through PGADmin (Provided by postgres) and command line utility "psql" and the trigger function is added but while executing through ANT it fails everytime
BEGIN TRANSACTION;
CREATE OR REPLACE FUNCTION sweeper() RETURNS trigger as '
DECLARE
timeout integer;
BEGIN
timeout = 30 * 24 * 60 * 60 ;
DELETE FROM diagnosticdata WHERE current_timestamp - teststarttime > (timeout * ''1 sec''::interval);
return NEW;
END;
' LANGUAGE 'plpgsql';
-- Trigger: sweep on diagnosticdata
CREATE TRIGGER sweep
AFTER INSERT
ON diagnosticdata
FOR EACH ROW
EXECUTE PROCEDURE sweeper();
END;
I encountered this error in liquibase and this page was one of the first search results so I guess I share my solution at this page:
You can put your whole sql in a separate file and include this in the changeset.
Its important to set the splitStatements option to false.
The whole changeset would then look like
<changeSet author="fgrosse" id="530b61fec3ac9">
<sqlFile path="your_sql_file_here.sql" splitStatements="false"/>
</changeSet>
I always like to have those big SQL parts (like function updates and such) in separate files.
This way you get proper syntax highlighting when opening the sql file and dont have to intermix XML and SQL in one file.
Edit: as mentioned in the comments its worth noting that the sql change supports the splitStatements option as well (thx to AndreyT for pointing that out).
I had the same problem with the JDBC driver used by Liquibase.
It seems that the driver explodes each line ended by a semicolon and runs it as a separate SQL command. That is why the code below will be executed by the JDBC driver in the following sequence:
CREATE OR REPLACE FUNCTION test(text) RETURNS VOID AS ' DECLARE tmp text
BEGIN tmp := "test"
END;
' LANGUAGE plpgsql
Of course, this is invalid SQL and causes the following error:
unterminated dollar-quoted string at or near ' DECLARE tmp text
To correct this, you need to use backslashes after each line ended with semicolon:
CREATE OR REPLACE FUNCTION test(text)
RETURNS void AS ' DECLARE tmp text; \
BEGIN
tmp := "test"; \
END;' LANGUAGE plpgsql;
Alternatively, you can place the whole definition in one line.
I am using HeidiSQL client and this was solved by placing DELIMITER // before CREATE OR REPLACE statement. There is a also a 'Send batch in one go' option in HeidiSQL that essentially achieves the same thing.
This error arises as an interaction between the particular client used to connect to the server and the form of the function. To illustrate:
The following code will run without casualty in Netbeans 7, Squirrel, DbSchema, PgAdmin3
CREATE OR REPLACE FUNCTION author.revision_number()
RETURNS trigger AS
$BODY$
begin
new.rev := new.rev + 1;
new.revised := current_timestamp;
return new;
end;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
Please note that the 'begin' statement comes immediately after the '$' quoted string.
The next code will halt all the above clients except PgAdmin3.
CREATE OR REPLACE FUNCTION author.word_count()
RETURNS trigger AS
$BODY$
declare
wordcount integer := 0; -- counter for words
indexer integer := 1; -- position in the whole string
charac char(1); -- the first character of the word
prevcharac char(1);
begin
while indexer <= length(new.blab) loop
charac := substring(new.blab,indexer,1); -- first character of string
if indexer = 1 then
prevcharac := ' '; -- absolute start of counting
else
prevcharac := substring(new.blab, indexer - 1, 1); -- indexer has increased
end if;
if prevcharac = ' ' and charac != ' ' then
wordcount := wordcount + 1;
end if;
indexer := indexer + 1;
end loop;
new.words := wordcount;
return new;
end;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
The crucial difference in the second example is the 'declare' section. The ploy of using back-slashes raises an error with PgAdmin3.
In summary I suggest trying different tools. Some tools even though they are supposed to be writing text files put invisible stuff into the text. Notoriously this occurs with the Unicode BOM which will halt any php file that tries to implement sessions or namespaces.
Whilst this is no solution I hope it helps.
I had the same problem with zeos and c++ builder.
The solution in my case:
Change the property delimiter (usually ";") to another in the component (class) I used.
dm->ZSQLProcessor1->DelimiterType=sdGo;
Perhaps Ant have something similar.
I know this question was asked a long time ago but I had kind of the same issue with a Postgresql script (run from Jenkins) using Ant's SQL Task.
I tried to run this SQL (saved in a file named audit.sql):
DROP SCHEMA IF EXISTS audit CASCADE
;
CREATE SCHEMA IF NOT EXISTS audit AUTHORIZATION faktum
;
CREATE FUNCTION audit.extract_interval_trigger ()
RETURNS trigger AS $extractintervaltrigger$
BEGIN
NEW."last_change_ts" := current_timestamp;
NEW."last_change_by" := current_user;
RETURN NEW;
END;
$extractintervaltrigger$ LANGUAGE plpgsql
;
but got the error "unterminated dollar-quoted string". No problem running it from pgAdmin.
I found out that it is not the driver that split the script at every ";" but rather Ant.
At http://grokbase.com/t/postgresql/pgsql-jdbc/06cjx3s3y0/ant-sql-tag-for-dollar-quoting I found the answer:
Ant eats double-$$ as part of its variable processing. You have to use
$BODY$ (or similar) in the stored procs, and put the delimiter on its
own line (with delimitertype="row"). Ant will cooperate then.
My Ant SQL script looks like this and it works:
<sql
driver="org.postgresql.Driver" url="jdbc:postgresql://localhost:5432/jenkins"
userid="user" password="*****"
keepformat="true"
autocommit="true"
delimitertype="row"
encoding="utf-8"
src="audit.sql"
/>
This example worked for me with PostgreSQL 14.1 and HeidiSQL 9.4.0.5125
DROP TABLE IF EXISTS emp;
CREATE TABLE emp (
empname text NOT NULL,
salary integer
);
DROP TABLE IF EXISTS EMP_AUDIT;
CREATE TABLE emp_audit(
operation char(1) NOT NULL,
stamp timestamp NOT NULL,
userid text NOT NULL,
empname text NOT NULL,
salary integer
);
DELIMITER //
CREATE OR REPLACE FUNCTION process_emp_audit() RETURNS TRIGGER AS $$
BEGIN
--
-- Create a row in emp_audit to reflect the operation performed on emp,
-- make use of the special variable TG_OP to work out the operation.
--
IF (TG_OP = 'DELETE') THEN
INSERT INTO emp_audit SELECT 'D', now(), user, OLD.*;
RETURN OLD;
ELSIF (TG_OP = 'UPDATE') THEN
INSERT INTO emp_audit SELECT 'U', now(), user, NEW.*;
RETURN NEW;
ELSIF (TG_OP = 'INSERT') THEN
INSERT INTO emp_audit SELECT 'I', now(), user, NEW.*;
RETURN NEW;
END IF;
RETURN NULL; -- result is ignored since this is an AFTER trigger
END;
$$ LANGUAGE plpgsql;
DROP TRIGGER IF EXISTS emp_audit ON emp;
CREATE TRIGGER emp_audit
AFTER INSERT OR UPDATE OR DELETE ON emp
FOR EACH ROW EXECUTE PROCEDURE process_emp_audit();
I was receiving the same error because I had my semicolon in a new line like this:
WHERE colA is NULL
;
Make sure they are in a single line as
WHERE colA is NULL;