I have .json file.C:/ a.json Table with column 'food' of type jsonb
how to insert the content of a.json into column 'food'
What are you using as your client, for example psql, Java program, Python program, etc.?
What version of Postgres are you using? In this case it probably does not matter that much, but json/jsonb has changed a good deal over recent versions so it is nice to know what you are working with.