http://www.postgresonline.com/journal/archives/201-Using-RETURNS-TABLE-vs.-OUT-parameters.html
--http://www.postgresonline.com/journal/archives/201-Using-RETURNS-TABLE-vs.-OUT-parameters.html --ver:9.3 Geovin Du 涂聚文 --returning a single record using SQL function CREATE OR REPLACE FUNCTION fn_sqltestout(param_subject text, pos integer) RETURNS TABLE(subject_scramble text, subject_char text) AS $$ SELECT substring($1, 1,CAST(random()*length($1) As integer)) , substring($1, 1,1) As subject_char; $$ LANGUAGE ‘sql‘ VOLATILE; -- example use SELECT (fn_sqltestout(‘This is a test subject‘,1)).subject_scramble; SELECT subject_scramble, subject_char FROM fn_sqltestout(‘This is a test subject‘,5); --Same function but written in plpgsql --PLPGSQL example -- return one record CREATE OR REPLACE FUNCTION fn_plpgsqltestout(param_subject varchar) RETURNS TABLE(subject_scramble varchar, subject_char varchar) AS $$ BEGIN subject_scramble := substring($1, 1,CAST(random()*length($1) As varchar)); subject_char := substring($1, 1,1); RETURN NEXT; END; $$ LANGUAGE ‘plpgsql‘ VOLATILE; -- example use SELECT (fn_plpgsqltestout(‘This is a test subject‘)).subject_scramble; SELECT subject_scramble, subject_char FROM fn_plpgsqltestout(‘This is a test subject‘); -- test data to use -- CREATE TABLE testtable(id integer PRIMARY KEY, test text); INSERT INTO testtable(id,test) VALUES (1, ‘Potato‘), (2, ‘Potato‘), (3, ‘Cheese‘), (4, ‘Cheese Dog‘); --SQL function returning multiple records CREATE OR REPLACE FUNCTION fn_sqltestmulti(param_subject varchar) RETURNS TABLE(test_id integer, test_stuff text) AS $$ SELECT id, test FROM testtable WHERE test LIKE $1; $$ LANGUAGE ‘sql‘ VOLATILE; -- example use SELECT (fn_sqltestmulti(‘Cheese%‘)).test_stuff; SELECT test_stuff FROM fn_sqltestmulti(‘Cheese%‘); -- plpgsql function returning multiple records -- note RETURN QUERY was introduced in 8.3 -- variant 1 CREATE OR REPLACE FUNCTION fn_plpgsqltestmulti(param_subject varchar) RETURNS TABLE(test_id integer, test_stuff text) AS $$ BEGIN RETURN QUERY SELECT id, test FROM testtable WHERE test LIKE param_subject; END; $$ LANGUAGE ‘plpgsql‘ VOLATILE; --测试 select * from fn_plpgsqltestmulti(‘Cheese%‘); -- variant 2 use this if you need to do something additional -- or conditionally return values or more dynamic stuff -- RETURN QUERY is generally more succinct and faster CREATE OR REPLACE FUNCTION fn_plpgsqltestmulti(param_subject varchar) RETURNS TABLE(test_id integer, test_stuff text) AS $$ DECLARE var_r record; BEGIN FOR var_r IN(SELECT id, test FROM testtable WHERE test LIKE param_subject) LOOP test_id := var_r.id ; test_stuff := var_r.test; RETURN NEXT; END LOOP; END; $$ LANGUAGE ‘plpgsql‘ VOLATILE; -- example use -- This is legal in PostgreSQL 8.4+ -- (prior versions plpgsql could not be called this way) SELECT (fn_plpgsqltestmulti(‘Cheese%‘)).test_stuff; SELECT * FROM fn_plpgsqltestmulti(‘Cheese%‘);
--函数 涂聚文 Geovin Du CREATE FUNCTION check_password(uname TEXT, pass TEXT) RETURNS BOOLEAN AS $$ DECLARE passed BOOLEAN; BEGIN SELECT (pwd = $2) INTO passed FROM pwds WHERE username = $1; RETURN passed; END; $$ LANGUAGE plpgsql SECURITY DEFINER -- Set a secure search_path: trusted schema(s), then ‘pg_temp‘. SET search_path = admin, pg_temp; ---http://www.postgresql.org/docs/current/static/sql-createfunction.html CREATE OR REPLACE function f_GetDepartmentName ( did integer ) returns varchar as $$ declare str varchar; begin select DepartmentName INTO str from DepartmentList where DepartmentID=did; return str; end; $$language plpgsql; --测试 select f_GetDepartmentName(1) as name; --( (select DepartmentName from DepartmentList where DepartmentID = in_id) union (select name from test_result2 where id = in_id) ) CREATE OR REPLACE FUNCTION func_DepartmentMore ( in_id integer) RETURNS SETOF varchar as $$ DECLARE v_name varchar; BEGIN for v_name in (select DepartmentName from DepartmentList where DepartmentID = in_id)loop RETURN NEXT v_name; end loop; return; END; $$ LANGUAGE PLPGSQL; --- select func_DepartmentMore(1); --- CREATE OR REPLACE FUNCTION func_DepartmentName_muti (in_id integer) RETURNS SETOF RECORD as $$ DECLARE v_rec RECORD; BEGIN for v_rec in (select DepartmentID,DepartmentName from DepartmentList where DepartmentID = in_id)loop RETURN NEXT v_rec; end loop; return; END; $$ LANGUAGE PLPGSQL; --测试 select * from func_DepartmentName_muti(1) t(DepartmentID integer,DepartmentName varchar); CREATE OR REPLACE FUNCTION func_DepartmentName_query ( in_id integer) RETURNS SETOF RECORD as $$ DECLARE v_rec RECORD; BEGIN return query(select DepartmentID,DepartmentName from DepartmentList where DepartmentID = in_id); return; END; $$ LANGUAGE PLPGSQL; --测试 select * from func_DepartmentName_query(1) t(DepartmentID integer,DepartmentName varchar); ---http://www.postgresonline.com/journal/archives/129-Use-of-OUT-and-INOUT-Parameters.html CREATE OR REPLACE FUNCTION func_DepartmentName_out( in_id integer,out o_id integer,out o_name varchar) RETURNS SETOF RECORD as $$ DECLARE v_rec RECORD; BEGIN for v_rec in ( select DepartmentID,DepartmentName from DepartmentList where DepartmentID = in_id)loop o_id := v_rec.DepartmentID; o_name := v_rec.DepartmentName; RETURN NEXT ; end loop; return; END; $$ LANGUAGE PLPGSQL; --测试 select DepartmentID,DepartmentName from DepartmentList select * from func_DepartmentName_out(1); select * from func_DepartmentName_out(2); --- CREATE OR REPLACE FUNCTION func_table(in_id int) RETURNS TABLE(f1 int, f2 varchar) AS $$ begin SELECT f1=DepartmentID, f2=DepartmentName from DepartmentList where DepartmentID =in_id; end; $$ LANGUAGE SQL; SELECT * FROM dup(42); CREATE OR REPLACE FUNCTION fn_plpgsqltestout(param_subject text, OUT subject_scramble text, OUT subject_char text) AS $$ BEGIN subject_scramble := substring($1, 1,CAST(random()*length($1) As integer)); subject_char := substring($1, 1,1); END; $$ LANGUAGE ‘plpgsql‘ VOLATILE; --测试 select fn_plpgsqltestout(‘geovindu‘); CREATE OR REPLACE FUNCTION fn_sqltestmulti(param_subject varchar, OUT test_id integer, OUT test_stuff text) RETURNS SETOF record AS $$ SELECT DepartmentID,DepartmentName FROM DepartmentList where DepartmentName LIKE $1; $$ LANGUAGE ‘sql‘ VOLATILE; --测试 SELECT * FROM fn_sqltestmulti(‘%d%‘); --OUT takes precendence which is why we prefix the table columns CREATE OR REPLACE FUNCTION fn_plpgsqltestmulti( param_subject varchar, OUT test_id integer, OUT test_stuff varchar) RETURNS SETOF record AS $$ BEGIN RETURN QUERY SELECT t.DepartmentID , t.DepartmentName FROM DepartmentList As t WHERE t.DepartmentName LIKE param_subject; END; $$ LANGUAGE ‘plpgsql‘ VOLATILE; SELECT * FROM fn_plpgsqltestmulti(‘%d%‘,1, ‘d‘);
时间: 2024-10-10 04:49:02