Dynamic query splicing error,a fuction use falie - postgresql

Question

I want to use the cursor to get the count(data) in all tables under the schema I need.
But I am unfamiliar with SQL, and I still cannot pass the following code:
CREATE OR REPLACE FUNCTION check_tool.get_nae(v_dbName character varying)
RETURNS numeric
LANGUAGE edbspl
SECURITY DEFINER
AS $function$
numInsert numeric;
numCal numeric;
v_result numeric;
query TEXT DEFAULT '';
cursor c_pj is
select t.table_schema::text as tableSchema,
t.table_name::text as tableName
from information_schema.tables t
where t.table_catalog = v_dbName
and t.table_type = 'BASE TABLE'
and t.table_schema in (select schema_name from check_tool.img_schema where dbName = v_dbName);
BEGIN
v_result := -1;
numInsert := 0;
for r_pj in c_pj loop
query := 'select count(*) from '||tableSchema||'.'||tableName||';'; -- select count(*) from "item"."project";
execute query into numCal;
insert into check_tool.img_result(schema_name,table_name,num) values (r_pj.tableSchema,r_pj.tableName,numCal);
numInsert := numInsert + 1;
if numInsert > 1000 then
numInsert := 0;
commit;
end if;
end loop;
commit;
v_result := 0;
RETURN v_result;
EXCEPTION
WHEN others THEN
RETURN v_result;
END get_nae$function$
;
/
I also tried concat() and quote_ident(), but the result is not ideal.

Answer 1

Dynamic SQL should be constructed using format() to better handle identifiers. In Postgres you can't commit inside a function, only in a procedure. Committing in a loop rarely improves the performance to begin with, so I would just skip that. I also wouldn't hide the real error (by just returning -1 or 0) but simply let any exception reach the caller of the procedure. And language edbspl is nothing I know, but in PL/pgSQL I would write it like this:
CREATE OR REPLACE PROCEDURE check_tool.get_nae(v_dbName character varying)
LANGUAGE plpgsql
AS
$body$
declare --<< required in PL/pgSQL to declare variables
numcal numeric;
query TEXT DEFAULT '';
l_rec record;
BEGIN
for l_rec in select t.table_schema::text as tableschema, t.table_name::text as tablename
from information_schema.tables t
where t.table_catalog = v_dbName
and t.table_type = 'BASE TABLE'
and t.table_schema in (select schema_name from check_tool.img_schema where dbName = v_dbName)
loop
query := format('select count(*) from %I.%I', l_rec.tableschema, l_rec.tablename);
execute query into numcal;
insert into check_tool.img_result(schema_name,table_name,num) values (l_rec.tableschema, l_rec.tablename, numcal);
end loop;
commit;
END;
$body$
;
Note that the condition t.table_catalog = v_dbName is actually useless, because you can't query tables that are not in the current database anyway.
Note that you don't really need a stored procedure to do this. You can use query_to_xml() to do this in a single SQL query by adjusting this answer
insert into check_tool.img_result(schema_name,table_name,num)
select table_schema,
table_name,
(xpath('/row/cnt/text()', xml_count))[1]::text::int as row_count
from (
select table_name, table_schema,
query_to_xml(format('select count(*) as cnt from %I.%I', table_schema, table_name), false, true, '') as xml_count
from information_schema.tables
where t.table_type = 'BASE TABLE'
and t.table_schema in (select schema_name from check_tool.img_schema)
) t;