PostgreSQL数据库中匿名块的写法实例

test=# DO $$DECLARE i record;
test$# BEGIN
test$# FOR i IN 1..10
test$# LOOP 
test$# execute 'select loop_insert(1)';
test$# END LOOP;
test$# END$$;
DO
test=# 

test=# select count(*) from lineitem;
 count 
-------
 7000
(1 row) 
test=# select count(*) from lineitem;
 count 
-------
 17000 ------------->>>>匿名块插入了10000条记录.
(1 row) 
test=# 

[ <<label>> ]
[ DECLARE
 declarations ]
BEGIN
 statements;
 ...
END [ label ];

DO $$
<<first_block>>
DECLARE
 counter integer := 0;
BEGIN
 counter := counter + 1;
 RAISE NOTICE 'The current value of counter is %', counter;
END first_block $$;

NOTICE: The current value of counter is 1 

DO
'<<first_block>>
DECLARE
 counter integer := 0;
BEGIN 
 
 counter := counter + 1;
 RAISE NOTICE ''The current value of counter is %'', counter; 
END first_block';

DO $$ 
<<outer_block>>
DECLARE
 counter integer := 0;
BEGIN 
 counter := counter + 1;
 RAISE NOTICE 'The current value of counter is %', counter;
 
 DECLARE 
 counter integer := 0;
 BEGIN 
 counter := counter + 10;
 RAISE NOTICE 'The current value of counter in the subblock is %', counter;
 RAISE NOTICE 'The current value of counter in the outer block is %', outer_block.counter;
 END;
 
 RAISE NOTICE 'The current value of counter in the outer block is %', counter;

NOTICE: The current value of counter is 1
NOTICE: The current value of counter in the subblock is 10
NOTICE: The current value of counter in the outer block is 1
NOTICE: The current value of counter in the outer block is 1