CODEWITHSUNDEEP
sqlpostgresqlpostgresql-9.4
Catherine
Catherine

Reputation: 13

How to create a view in sql that takes parameters

I want to create a view that takes parameters and then make a selection on this view like this

CREATE OR REPLACE FUNCTION statistiquess(dateDeb date, dateFin date)
RETURNS void AS
$$
     CREATE OR REPLACE VIEW statistics 
     AS 
      SELECT 
         e.matricule_ens, 
         e.nom_ens, 
         e.prenom_ens, 
         m.code_matiere, 
         m.nom_matiere, 
         f.id_formation, 
         f.nom_formation, 
         SUM ((CAST (c.heure_fin AS TIME))-(CAST (c.heure_deb AS TIME))) AS heure_total_programme, 
         SUM ((CAST (c.heure_dep_ens AS TIME))-(CAST (c.heure_arr_ens AS TIME))) AS heure_total_enseigne 
     FROM 
         enseignant e inner join cours c on e.matricule_ens = c.matricule_ens 
         inner join matiere m on c.code_matiere =  m.code_matiere 
         inner join formation f on f.id_formation = c.id_formation 
     WHERE
       c.jour between dateDeb and dateFin
     GROUP BY 
        e.matricule_ens, m.code_matiere, f.id_formation 
     ORDER BY 
        e.nom_ens;
$$
LANGUAGE SQL;

I have this error when i try to select all from function like this

select * from statistiquess('2019-03-06', '2019-03-29');

ERREUR: la colonne « datedeb » n'existe pas

LINE 6: ..._formation = c.id_formation where (c.jour between datedeb an...


QUERY:  
     CREATE OR REPLACE VIEW statistics AS select e.matricule_ens, e.nom_ens, e.prenom_ens, m.code_matiere, m.nom_matiere, f.id_formation, f.nom_formation, 
     SUM ((CAST (c.heure_fin AS TIME))-(CAST (c.heure_deb AS TIME))) AS heure_total_programme, 
     SUM ((CAST (c.heure_dep_ens AS TIME))-(CAST (c.heure_arr_ens AS TIME))) AS heure_total_enseigne 
     from enseignant e inner join cours c on e.matricule_ens = c.matricule_ens inner join matiere m on c.code_matiere =  m.code_matiere 
     inner join formation f on f.id_formation = c.id_formation where (c.jour between datedeb and datefin) 
     GROUP BY e.matricule_ens, m.code_matiere, f.id_formation ORDER BY e.nom_ens;

Upvotes: 0

Views: 188

Answers (2)

user330315
user330315

Reputation:

You don't need to create a view inside the function to do that. Just return the result of the query from within the function:

CREATE OR REPLACE FUNCTION statistiquess(dateDeb date, dateFin date)
RETURNS tables (matricule_ens text, nom_ens text, prenom_ens text, 
               code_matiere text, nom_matiere text, id_formation int,
               nom_formation text, heure_total_programme bigint, 
               heure_total_enseigne bigtin) AS
$$
    SELECT 
       e.matricule_ens, 
       e.nom_ens, 
       e.prenom_ens, 
       m.code_matiere, 
       m.nom_matiere, 
       f.id_formation, 
       f.nom_formation, 
       SUM ((CAST (c.heure_fin AS TIME))-(CAST (c.heure_deb AS TIME))) AS heure_total_programme, 
       SUM ((CAST (c.heure_dep_ens AS TIME))-(CAST (c.heure_arr_ens AS TIME))) AS heure_total_enseigne 
    FROM 
       enseignant e inner join cours c on e.matricule_ens = c.matricule_ens 
       inner join matiere m on c.code_matiere =  m.code_matiere 
       inner join formation f on f.id_formation = c.id_formation 
    WHERE
     c.jour between dateDeb and dateFin
    GROUP BY 
      e.matricule_ens, m.code_matiere, f.id_formation 
    ORDER BY 
      e.nom_ens;
$$
LANGUAGE SQL;

You will have to adjust the data types of the returned columns (inside the table (...) part) - I only guessed what they could be.

Then you can use it like a "view with parameters":

select * 
from statistiquess('2019-03-06', '2019-03-29');

Upvotes: 0

denov
denov

Reputation: 12688

the syntax you have above has function not a view like as the title says. only functions and stored procedures can take parameters. function return a value and stored procedures don't. the syntax for a function is

CREATE [OR REPLACE] FUNCTION function_name (arguments) 
RETURNS return_datatype AS $variable_name$
   DECLARE
      declaration;
      [...]
   BEGIN
      < function_body >
      [...]
      RETURN { variable_name | value }
   END; LANGUAGE plpgsql;

the syntax for a stored procedure

CREATE [OR REPLACE] PROCEDURE procedure_name(parameter_list)
LANGUAGE language_name
AS $$
    stored_procedure_body;
$$;

a view is a stored query that you can query like any other table.

SELECT * FROM statistiquess WHERE c.jour BETWEEN '2019-03-06' AND '2019-03-29';

without understanding your data and use case it's hard to say which one you should use. from your question it sounds like you either need a view or stored procedure.

Upvotes: 1

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