Concatenate multiple fields in query string in plpgsql

Question

I am using plpgsql and hibernate and want to create a function which contains the query string given below. In the select clause I want to concatenate 3 fields but while running this query I am getting error message like:

ERROR: syntax error at or near "' '"
SQL state: 42601
Context: PL/pgSQL function "est_fn_dept_wise_emp_report" line 30 at open

I am new using stored functions, it might be a basic question but somehow I was unable to find a solution.

 query1 = 'SELECT  est_emp_empmaster.emp_no AS est_emp_empmaster_emp_no,
            adm_m_department.dept_name AS adm_m_department_dept_name,
            adm_m_subdepartment.sub_dept_id AS adm_m_subdepartment_sub_dept_id,
            adm_m_subdepartment.sub_dept_name AS adm_m_subdepartment_sub_dept_name,
            est_m_designation.desig_name AS est_m_designation_desig_name,
            est_emp_empmaster.first_name'|| ' ' ||'est_emp_empmaster.middle_name'|| ' '               ||'est_emp_empmaster.surname AS empname
    FROM public.adm_m_department adm_m_department
        INNER JOIN public.adm_m_subdepartment adm_m_subdepartment
        ON adm_m_department.dept_id = adm_m_subdepartment.dept_id
        INNER JOIN public.est_emp_empmaster est_emp_empmaster
        ON adm_m_department.dept_id = est_emp_empmaster.dept_id
        AND adm_m_subdepartment.sub_dept_id = est_emp_empmaster.sub_dept_id
        INNER JOIN public.est_emp_salary est_emp_salary
        ON est_emp_empmaster.emp_no = est_emp_salary.emp_no
        INNER JOIN public.est_m_designation est_m_designation
        ON est_emp_salary.pre_desig_code = est_m_designation.desig_code
        AND est_emp_salary.retired_flag ='|| quote_literal('N') ||'
         WHERE   est_emp_empmaster.corp_coun_id=0 or est_emp_empmaster.corp_coun_id is null or est_emp_empmaster.corp_coun_id = '|| quote_literal($1) ||'
         ORDER BY adm_m_department.dept_id,adm_m_subdepartment.sub_dept_id,est_emp_empmaster.emp_no ASC';


    OPEN refcur FOR
         EXECUTE query1;
    LOOP
         FETCH refcur INTO return_record;
         EXIT WHEN NOT FOUND;
         RETURN NEXT return_record;
    END LOOP;
    CLOSE refcur;**

The above query runs fine if I execute it without executing through query string. But as I want to use this query for multiple conditions and in those condition I want to modify this query to get different results.

Answer 1

This can be much simpler, safer and faster (assuming at least Postgres 8.4):

 CREATE OR REPLACE FUNCTION foo(_corp_coun_id int) -- guessing type
  RETURNS TABLE (
    emp_no        int  -- guessing data types ..
   ,dept_name     text -- .. replace with actual types
   ,sub_dept_id   int
   ,sub_dept_name text
   ,desig_name    text
   ,empname       text) AS
$func$
BEGIN

RETURN QUERY
SELECT em.emp_no
      ,dp.dept_name
      ,sb.sub_dept_id
      ,sb.sub_dept_name
      ,ds.desig_name
      ,concat_ws(' ', em.first_name, em.middle_name, em.surname) --  AS empname
FROM   adm_m_department    dp
JOIN   adm_m_subdepartment su ON sb.dept_id = dp.dept_id
JOIN   est_emp_empmaster   em ON em.dept_id = sb.dept_id 
                             AND em.sub_dept_id = sb.sub_dept_id
JOIN   est_emp_salary      sl ON sl.emp_no = em.emp_no
                             AND sl.retired_flag = 'N'    -- untangled join cond.
JOIN   est_m_designation   ds ON ds.desig_code = sl.pre_desig_code
WHERE  em.corp_coun_id = 0 OR
       em.corp_coun_id IS NULL OR
       em.corp_coun_id = $1
ORDER  BY dp.dept_id, sb.sub_dept_id, em.emp_no;

END    
$func$
  LANGUAGE plpgsql SET search_path=public;

• To address your primary question: use concat_ws() for simple and secure concatenation of multiple columns (doesn't fail with NULL).

• You do not need dynamic SQL here since the variables are only values (not identifiers).

• You do not need a CURSOR here.

• You do not need a LOOP. RETURN QUERY does the same, simpler and faster.

• You do not need column aliases, only the names of the OUT parameters (implicitly the column names in RETURNS TABLE (...)) are relevant.

• Replace the multiple schema qualification public. in your query with a single SET search_path = public.

• I also untangled your query, used short table aliases and reformatted to make it easier to read.

• You don't even need plpgsql at all here. Can be a simpler SQL function:

 CREATE OR REPLACE FUNCTION foo(_corp_coun_id int)
  RETURNS TABLE (
    emp_no        int  -- guessing data types ..
   ,dept_name     text -- .. replace with actual types!
   ,sub_dept_id   int
   ,sub_dept_name text
   ,desig_name    text
   ,empname       text) AS
$func$
SELECT em.emp_no
      ,dp.dept_name
      ,sb.sub_dept_id
      ,sb.sub_dept_name
      ,ds.desig_name
      ,concat_ws(' ', em.first_name, em.middle_name, em.surname) --  AS empname
FROM   adm_m_department    dp
JOIN   adm_m_subdepartment sb ON sb.dept_id = dp.dept_id
JOIN   est_emp_empmaster   em ON em.dept_id = sb.dept_id 
                             AND em.sub_dept_id = sb.sub_dept_id
JOIN   est_emp_salary      sl ON sl.emp_no = em.emp_no
                             AND sl.retired_flag = 'N'    -- untangled join cond.
JOIN   est_m_designation   ds ON ds.desig_code = sl.pre_desig_code
WHERE  em.corp_coun_id = 0 OR
       em.corp_coun_id IS NULL OR
       em.corp_coun_id = $1
ORDER  BY dp.dept_id, sb.sub_dept_id, em.emp_no;
$func$
  LANGUAGE sql SET search_path=public;

Answer 2

I found a solution to the above problem, actually it was well working in normal query but i got problem while running it in dynamic query. The solution to the above problem is as follows.Thanks again.. :)

est_emp_empmaster.first_name||'' ''||est_emp_empmaster.middle_name||'' ''||est_emp_empmaster.surname AS empname