plpgsql

问题 How to have the break statement in PostgreSQL? I have the structure like this: for() { for() { if(somecondition) break; } } As per my understanding it should only break the inner for loop? 回答1: There is no BREAK in PL/pgSQL. EXIT terminates the loop. CONTINUE continues at the next iteration of the loop. You can attach a <<label>> to loops and add it as parameter to each of these commands. Then you terminate / continue the labeled loop. Else, it concerns the inner loop. RETURN exits from the

问题 How to have the break statement in PostgreSQL? I have the structure like this: for() { for() { if(somecondition) break; } } As per my understanding it should only break the inner for loop? 回答1: There is no BREAK in PL/pgSQL. EXIT terminates the loop. CONTINUE continues at the next iteration of the loop. You can attach a <<label>> to loops and add it as parameter to each of these commands. Then you terminate / continue the labeled loop. Else, it concerns the inner loop. RETURN exits from the

问题 i have a storerd procedure like below, CREATE FUNCTION select_transactions3(text, text, int) RETURNS SETOF transactions AS $body$ DECLARE rec transactions%ROWTYPE; BEGIN FOR rec IN (SELECT invoice_no, trans_date FROM transactions WHERE $1 = $2 limit $3 ) LOOP RETURN NEXT rec; END LOOP; END; $body$ LANGUAGE plpgsql VOLATILE SECURITY DEFINER; when i execute query like this : select * from select_transactions3("invoice_no", '1103300105472',10); or select * from select_transactions3(invoice_no,

问题 i have a storerd procedure like below, CREATE FUNCTION select_transactions3(text, text, int) RETURNS SETOF transactions AS $body$ DECLARE rec transactions%ROWTYPE; BEGIN FOR rec IN (SELECT invoice_no, trans_date FROM transactions WHERE $1 = $2 limit $3 ) LOOP RETURN NEXT rec; END LOOP; END; $body$ LANGUAGE plpgsql VOLATILE SECURITY DEFINER; when i execute query like this : select * from select_transactions3("invoice_no", '1103300105472',10); or select * from select_transactions3(invoice_no,

问题 I am using a function CREATE FUNCTION myfunc() RETURNS trigger AS $$ ... $$ LANGUAGE plpgsql; with a trigger, CREATE TRIGGER mycheck BEFORE INSERT OR UPDATE ON t FOR EACH ROW EXECUTE PROCEDURE myfunc(); My problem now is to express in the body of myfunc() a condition about events, a plpgsql like IF TRIGGER_EVENT_WAS_INSERT THEN ...doThis... END IF; How to express this condition? (see that I have "INSERT OR UPDATE" trigger event) I am using PostgreSQL v9.1. 回答1: Yes, TG_OP . Per documentation:

问题 When copying data from a file, you get the count of rows in psql with the "command tag": db=# COPY t FROM '/var/lib/postgres/test.sql'; COPY 10 I need the number of rows and would like to avoid a redundant count() on the table. Is there a way to get this count from COPY directly in a PL/pgSQL function? As far as I know there is none, but maybe I am missing something? For PostgreSQL 9.2. But any option in any version would be of interest. 回答1: Not in PG 9.2, but there is in PG 9.3 courtesy of

问题 I just wonder if anyone knows how to automatize views creation after running DROP ... CASCADE ? Now I'm trying to drop view at first with classic DROP VIEW myview statement and if I cannot drop the view because other objects still depend on it then checking out all the objects names that postgres lists and save their creates and then I run drop with cascade. Sometimes it's like over a dozen objects. But maybe you have got some idea to handle this issue in more automated way? Maybe anybody has

问题 I've just inherited an old PostgreSQL installation and need to do some diagnostics to find out why this database is running slow. On MS SQL you would use a tool such as Profiler to see what queries are running and then see how their execution plan looks like. What tools, if any, exist for PostgreSQL that I can do this with? I would appreciate any help since I´m quite new with Postgres. 回答1: Use pg_stat_statements extension to get long running queries. then use select* from pg_stat_statements

问题 This instruction works: SELECT INTO unsolvedNodes array_agg(DISTINCT idDestination) FROM road WHERE idOrigin = ANY(solvedNodes) AND NOT (idDestination = ANY(solvedNodes)); But I would like to use something this way: SELECT INTO unsolvedNodes array_agg(DISTINCT idDestination), lengths array_agg(length) FROM road WHERE idOrigin = ANY(solvedNodes) AND NOT (idDestination = ANY(solvedNodes)); How to use only one "SELECT INTO" instruction to set multiple variables? 回答1: In PL/pgSQL you can SELECT

问题 This instruction works: SELECT INTO unsolvedNodes array_agg(DISTINCT idDestination) FROM road WHERE idOrigin = ANY(solvedNodes) AND NOT (idDestination = ANY(solvedNodes)); But I would like to use something this way: SELECT INTO unsolvedNodes array_agg(DISTINCT idDestination), lengths array_agg(length) FROM road WHERE idOrigin = ANY(solvedNodes) AND NOT (idDestination = ANY(solvedNodes)); How to use only one "SELECT INTO" instruction to set multiple variables? 回答1: In PL/pgSQL you can SELECT