PL/SQL block error

Hello,
I am very new to the postgres sql, i am trying to execute below pl/sql block in postgres but i am getting error 'ERROR:  syntax error at or near "integer" ', Could some one help me in this regard

declare
v_count integer;
begin
select  count(1) into v_count  from  pg_index inx where  inx.indexrelid in
 (select oid from pg_class where relname='action_pk' and relowner in
 (select oid from pg_authid where rolname='postgres_ref'))
 and inx.indrelid in
 (select oid from pg_class where relname='action' and relowner in
 (select oid from pg_authid where rolname='postgres_ref'));

if v_count = 0 then 
execute immediate 'create unique index action_pk   
on action(acn_id)'; 
end if;
end

Sivannarayanareddy Nusum | System Analyst(Moneta GDO)

Subex Limited, Adarsh Tech Park, Outer Ring Road, Devarabisannalli, Bangalore – 560037, India.
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