Initialize a string in a stored function - postgresql

Question

I call this procedure without any problem :
SELECT SP_getGlobalVariable('current_user_id')::INT ;
If I call it inside another stored procedure like this :
-- Get current User Id --
SELECT SP_getGlobalVariable('current_user_id')::INT INTO __currentUserId ;
I have this error :
ERROR : Syntax error near "current_user_id"
LINE 25: SELECT SP_getGlobalVariable('current_user_id')::INT INTO _...
It is probably a stupid syntax error... If someone can help a poor MySQL user starting using PG !
EDIT 1 :
SELECT version();
PostgreSQL 9.3.3 on i686-pc-linux-gnu, compiled by gcc-4.4.real (Debian 4.4.5-8) 4.4.5, 32-bit
This is the result of the version() call.
CREATE OR REPLACE FUNCTION SP_getGlobalVariable (__variableName VARCHAR(64))
RETURNS VARCHAR
AS
'
DECLARE
BEGIN
RETURN (SELECT value FROM tmp_variables
WHERE name = __variableName) ;
END ;
'
LANGUAGE 'plpgsql';
The procedure to get the global variable in the temporary table.*
EDIT 2 :
CREATE OR REPLACE FUNCTION SP_insertSite (__siteName VARCHAR(70), __siteDescription TEXT, __siteLatitude NUMERIC, __siteLongitude NUMERIC)
RETURNS INT
AS
'
DECLARE
-- Variables
__right_edge_father INT ;
__left_edge_father INT ;
__depth_father INT ;
__nbrSites INT ;
__insertId INT ;
__currentUserId INT ;
BEGIN
-- Check if tree is empty --
SELECT COUNT(*) INTO __nbrSites
FROM site ;
-- Get current User Id --
SELECT SP_getGlobalVariable('current_user_id')::INT INTO __currentUserId ;
IF __nbrSites = 0 THEN
INSERT INTO site (site_name, site_description, site_latitude, site_longitude, site_left_edge, site_right_edge, site_depth, site_create_dt, site_create_user_id)
VALUES(__siteName, __siteDescription, 0.0, 0.0, 1, 2, 0, LOCALTIMESTAMP, __currentUserId)
RETURNING site_id INTO __insertId;
ELSE
-- Get father edges --
SELECT site_left_edge, site_right_edge, site_depth
INTO __left_edge_father, __right_edge_father, __depth_father
FROM site
WHERE site_id = (SELECT site_id FROM site WHERE site_depth = 0 LIMIT 1) ;
-- Updates left edges --
UPDATE site
SET site_left_edge = site_left_edge + 2
WHERE site_left_edge >= __right_edge_father ;
-- Updates right edges --
UPDATE site
SET site_right_edge = site_right_edge + 2
WHERE site_right_edge >= __right_edge_father ;
-- Insert new node --
INSERT INTO site (site_name, site_description, site_latitude, site_longitude, site_left_edge, site_right_edge, site_depth, site_create_dt, site_create_user_id)
VALUES(__siteName, __siteDescription, __siteLatitude, __siteLongitude, __right_edge_father, __right_edge_father+1, __depth_father+1, LOCALTIMESTAMP, __currentUserId)
RETURNING site_id INTO __insertId;
END IF ;
RETURN __insertId ;
END ;
'
LANGUAGE plpgsql;

Answer 1

The problem is that you are using single quotes to encapsulate the function body, and so, when you try to add single quotes inside the body, you need to escape it, for instance:
CREATE OR REPLACE FUNCTION SP_insertSite (...)
RETURNS INT
AS
'
DECLARE
...
-- Get current User Id --
SELECT SP_getGlobalVariable(''current_user_id'')::INT INTO __currentUserId ;
...
RETURN __insertId ;
END ;
'
LANGUAGE plpgsql;
That would work nice. But I recommend you to use dollar-quoting and so you don't have to worry with single-quote escaping inside the function body, as the following:
CREATE OR REPLACE FUNCTION SP_insertSite (...)
RETURNS INT
AS
$$
DECLARE
...
-- Get current User Id --
SELECT SP_getGlobalVariable('current_user_id')::INT INTO __currentUserId ;
...
RETURN __insertId ;
END ;
$$
LANGUAGE plpgsql;
I'd recommend you to read PostgreSQL docs about the usage of dollar-quoting in PL/pgSQL (the entire document, not just this sub-section is also interesting to read).