SELECT
  regexp_extract('https://docs.fluentd.org/v0.12/articles/out_file','(docs.fluentd.org).*(out_file)',1) AS pat1,
  regexp_extract('https://docs.fluentd.org/v0.12/articles/out_file','(docs.fluentd.org)(out_file)'  ,1) AS pat2,
  regexp_extract('https://docs.fluentd.org/v0.12/articles/out_file','(docs.fluentd.org|out_file)' ,1) AS pat3,

  regexp_extract('https://docs.fluentd.orgout_file','(docs.fluentd.org).*(out_file)',1) AS pat4,
  regexp_extract('https://docs.fluentd.orgout_file','(docs.fluentd.org)(out_file)'  ,1) AS pat5,
  regexp_extract('https://docs.fluentd.orgout_file','(docs.fluentd.org)(out_file)'  ,2) AS pat6,
  regexp_extract('https://docs.fluentd.orgout_file','(docs.fluentd.org|out_file)'   ,1) AS pat7,

  regexp_extract('https://docs.fluentd.org/v0.12/articles/out_forward','(docs.fluentd.org|out_file)',1) AS pat8,
  regexp_extract('https://docs.fluentd.org/v0.12/articles/out_file'   ,'(docs.fluentd.org|out_file)',1) AS pat9,
  regexp_extract('out_file/article/docs.fluentd.org/'                 ,'(docs.fluentd.org|out_file)',1) AS pat10

FROM access_log
LIMIT 1