因为双引号不能更新postgres DB中的字典列吗?

你应该能够反斜杠转义内部双引号:

psql -U postgres -c "UPDATE taskt SET update= '[{\"id\": 0, \"timestamp\": \"2019-12-17T22:16:28.985Z\", \"statusUpdate\": \"three little piggies\"}]' WHERE uri = '/rest/tasks/xyz';"

否则，你可以保存文件并运行:

cat <<_EOF_ > /tmp/myfile
> UPDATE taskt SET update= '[{"id": 0, "timestamp": "2019-12-17T22:16:28.985Z", "statusUpdate": "three little piggies"}]' WHERE uri = '/rest/tasks/xyz';
> _EOF_
psql -U postgres < /tmp/myfile

你还应该能够做一个heredoc直接到psql:

psql postgres postgres <<_EOF_
> select 1;
> _EOF_
 ?column? 
----------
        1
(1 row)
psql U postgres <<_EOF_
UPDATE taskt SET update= '[{"id": 0, "timestamp": "2019-12-17T22:16:28.985Z", "statusUpdate": "three little piggies"}]' WHERE uri = '/rest/tasks/xyz';
_EOF_