vertica提取json字段值

json字符串的内容如下：

[{"stockName":"阳光照明","stockProfit":"5500.0000","stockCode":"600261"},{"stockName":"京 运 通","stockProfit":"6664.5000","stockCode":"601908"}]

通过regexp_substr和regexp_instr函数来提取stockcode字段值，返回前3个值。SQL如下：

select
  substr(regexp_substr(f1, 'stockCode":"(\w)+'), 13) as code1,
  (case when regexp_instr(f1, 'stockCode":"(\w)+') > 0 then
    substr(regexp_substr(f1, 'stockCode":"(\w)+', regexp_instr(f1, 'stockCode":"(\w)+') + 1), 13) 
  else null end) as code2,
  (case when regexp_instr(f1, 'stockCode":"(\w)+') > 0 and regexp_instr(f1, 'stockCode":"(\w)+', regexp_instr(f1, 'stockCode":"(\w)+') + 1) > 0 then
    substr(regexp_substr(f1, 'stockCode":"(\w)+', regexp_instr(f1, 'stockCode":"(\w)+', regexp_instr(f1, 'stockCode":"(\w)+') + 1) + 1), 13)
  else null end) as code3
from t1