出版社記号を取り出す（Google BigQueryのDML）

stripPublisherID.sql

# 出版社記号を取り出す
# ISBN-10を想定

CREATE TEMP FUNCTION
  stripPublisherID(a STRING)
  RETURNS STRING
  LANGUAGE js AS """
     if(!a.length==10)return null;
     if(!a.startsWith('4'))return null;
     let ln = 0;
     let part = parseInt(a.substr(1,7));
     if(part>=0 && part<=1999999){
         ln=2;
     }else if(part>=2000000 && part<=5999999){
         ln=3;
     }else if(part>=6000000 && part<=6999999){
         ln=8;
     }else if(part>=7000000 && part<=8499999){
         ln=4;
     }else if(part>=8500000 && part<=8999999){
         ln=5;
     }else if(part>=9000000 && part<=9499999){
         ln=6;
     }else if(part>=9500000 && part<=9999999){
         ln=7;
     }
     return a.substr(1,ln);
  """;