jq pivot example for count.
jq -n '[{name:"a",date:"08/17"},{name:"a",date:"08/20"},{name:"b",date:"08/20"},{name:"b",date:"08/23"}]' | jq --arg rowfield "name" --arg columnfield "date" "$(curl -s https://gitee.com/zhangweis/deno-report-tools/raw/693d2db3ae8387873e18ec2264937708f0b0dd9c/pivot.jq)"