I\'ve got a a table with rows, and one of the rows has a field with data like this
{\"name\":\"Richard\",\"lastname\":null,\"city\":\"Olavarria\",\"cityId\":
This may be a little late, but the accepted answer didn't work for me. I used SUBSTRING_INDEX to achieve the desired result.
SELECT ID, SUBSTRING_INDEX(SUBSTRING_INDEX(JSON, '"mykey" : "', -1), '",', 1) MYKEY FROM MY_TABLE;
Hope this helps.