今天想在 Mac 上安裝 Python 套件 psycopg2 (用來存取 PostgreSQL) 時，

出現了錯誤訊息：

$ pip install psycopg2

Looking in indexes: https://pypi.org/simple, https://:****@jfrog.trendmicro.com/artifactory/api/pypi/tcp-python-sdk-local/simple
Collecting psycopg2
  Downloading psycopg2-2.9.10.tar.gz (385 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  error: subprocess-exited-with-error

  × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> [21 lines of output]
      running egg_info
      writing psycopg2.egg-info/PKG-INFO
      writing dependency_links to psycopg2.egg-info/dependency_links.txt
      writing top-level names to psycopg2.egg-info/top_level.txt

      Error: pg_config executable not found.

      pg_config is required to build psycopg2 from source.  Please add the directory
      containing pg_config to the $PATH or specify the full executable path with the
      option:

          python setup.py build_ext --pg-config /path/to/pg_config build ...

      or with the pg_config option in 'setup.cfg'.

      If you prefer to avoid building psycopg2 from source, please install the PyPI
      'psycopg2-binary' package instead.

      For further information please check the 'doc/src/install.rst' file (also at
      <https://www.psycopg.org/docs/install.html>).

      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× Getting requirements to build wheel did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

看起來是因為沒有 pg_config…

不過錯誤訊息也說如果你不打算從原始碼開始編譯的話，

可以用 psycopg2-binary 這個套件：

$ pip install psycopg2-binary

Looking in indexes: https://pypi.org/simple, https://:****@jfrog.trendmicro.com/artifactory/api/pypi/tcp-python-sdk-local/simple
Collecting psycopg2-binary
Downloading psycopg2_binary-2.9.10-cp311-cp311-macosx_14_0_arm64.whl (3.3 MB)
Installing collected packages: psycopg2-binary
Successfully installed psycopg2-binary-2.9.10

看來也是可以正常使用的喔：

$ python

Python 3.11.9 (main, Aug 12 2024, 18:16:47) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

>>> import psycopg2

>>> psycopg2.__version__
'2.9.10 (dt dec pq3 ext lo64)'