plpgsql

im working on a simple function where it automatically updates something from a table. create or replace function total() returns void as $$ declare sum int; begin sum = (SELECT count(copy_id) FROM copies); update totalbooks set all_books = sum where num = 1; end; $$ language plpgsql; if i execute "select total();" it works perfectly fine so i made a function trigger so that it automatically updates: create or replace function total1() returns trigger as $$ begin perform (select total()); return null; end; $$ language plpgsql; but after i execute this: create trigger total2 after update on

I am new to PostgreSQL and am using the query tool in PGAdmin. I'm trying to run pgsql queries that use variables, but I can't seem to get the syntax right. Here's a sample query that gives a syntax error: DECLARE num INTEGER; BEGIN num := 3; PRINT num; END; Update: Ok, let me try and explain. I come from a SQL server background. In the management studio, I can open a query window and play with (T)-SQL queries. For example, I can write something like this: DECLARE @num INT SET @num = 3 SELECT @num I know this is a dumb example, but I'm just trying to declare a variable and do something with it

I have a table in the database: create table store ( ... n_status integer not null, t_tag varchar(4) t_name varchar, t_description varchar, dt_modified timestamp not null, ... ); In my stored function I need to execute the same select against this table multiple times: select * from store where n_place_id = [different values] and t_tag is not null and n_status > 0 and (t_name ~* t_search or t_description ~* t_search) order by dt_modified desc limit n_max; Here, t_search and n_max are parameters into the stored function. I thought it would make sense to use a prepared statement for this, but I

I would like to record the id of a user in the session/transaction, using SET , so I could be able to access it later in a trigger function, using current_setting . Basically, I'm trying option n2 from a very similar ticket posted previously , with the difference that I'm using PG 10.1 . I've been trying 3 approaches to setting the variable: SET local myvars.user_id = 4 , thereby setting it locally in the transaction; SET myvars.user_id = 4 , thereby setting it in the session; SELECT set_config('myvars.user_id', '4', false) , which depending of the last argument, will be a shortcut for the

CREATE OR REPLACE FUNCTION _chkLogin(userid varchar, pwd varchar) RETURNS BOOLEAN AS $BODY$ DECLARE passed BOOLEAN; BEGIN SELECT (_password = $2) FROM _vRegistration WHERE _userid = $1; RETURN passed; END; $BODY$ LANGUAGE 'plpgsql'; When am executing the code above am getting the following error, SELECT _chkLogin('username','abcd') as passed; ERROR: query has no destination for result data I've used perform then i get a different problem, PERFORM _chkLogin('username','abcd'); ERROR: syntax error at or near "perform" Suggest me what should I be doing in order to overcome this error. You do

I have a text column that contains JSON and also plan text. I want to convert it to JSON, and then select a particular property. For example: user_data _________ {"user": {"name": "jim"}} {"user": {"name": "sally"}} some random data string I've tried: select user_data::json#>'{user,name}' from users I get: ERROR: invalid input syntax for type json DETAIL: Token "some" is invalid. CONTEXT: JSON user_data, line 1: some... Is it possible to prevent this? If you want to skip the rows with invalid JSON, you must first test if the text is valid JSON. You can do this by creating a function which will