找不到 postgresql 函数

Question

尝试运行 sha256 函数

CREATE EXTENSION pgcrypto;
CREATE OR REPLACE FUNCTION sha256(bytea) returns text AS $$
    SELECT encode(digest($1, 'sha256'), 'hex')
$$ LANGUAGE SQL STRICT IMMUTABLE;

WITH
tab_email as        (SELECT 'my@email.com'::text as email FROM tmp),
INSERT INTO users (email, password) VALUES ((SELECT email FROM tab_email), sha256('mypass'));

我收到这个错误

错误：函数 sha256(text) 不存在

Answer 1

这是因为 Postgres 的内置sha256函数需要一个bytea参数：

citus=> \df+ sha256
                                                                               List of functions
   Schema   |  Name  | Result data type | Argument data types | Type | Volatility | Parallel |  Owner   | Security | Access privileges | Language | Source code  | Description
------------+--------+------------------+---------------------+------+------------+----------+----------+----------+-------------------+----------+--------------+--------------
 pg_catalog | sha256 | bytea            | bytea               | func | immutable  | safe     | postgres | invoker  |                   | internal | sha256_bytea | SHA-256 hash
(1 row)

所以只需投射到::bytea第一个。

citus=> select encode(sha256('a'::bytea), 'hex');
                              encode
------------------------------------------------------------------
 ca978112ca1bbdcafac231b39a23dc4da786eff8147c4e72b9807785afee48bb
(1 row)