如何從sql oracle 9i中的字符串中提取日期

Question

我在表中有列說明（VARCHAR2）：

No| Explanation  
1 | Shipment of cabbage by agreement 29.04.2019 TAX Free  
2 | Payment for screws (01.04.19) Tax: 13.55 %  
3 | For reserch by deal dated 01.01.2015 Tax free  
4 | Tax payment for the may 2019 

我需要查詢，它會回答“條目是否有某種形式的日期？” 每個條目都是/否。 是否可以在Oracle 9i上使用？

我試過一些解決方案。 但遇到問題：

“ORA-01858：在預期數字的位置找到了非數字字符”。

我現在還不清楚datestamp將在哪個字段中。

select to_char(to_date(EXPLANATION, 'DD.MM.YYYY')) from PAYMENTDOC

Answer 1

您可以使用正則表達式執行此操作。 試試以下代碼：

  select No, Explanation, 
  case when regexp_instr(Explanation,'\d{2}.\d{2}.\d{2}')!=1 then 
              'Y'
              when regexp_instr(Explanation,'\d{2}.\d{2}.\d{4}')!=1 then
              'Y'
              when REGEXP_instr(Explanation, '(January|February|March|April|May|June|July|August|September|October|November|December) [0-9]{4}')!=1 then
              'Y'
             END Does_entry_have_a_date_in_some_form_in_it
  from table_name;

輸出：

No| Explanation                                          | Does_entry_have_a_date_in_some_form_in_it
1 | Shipment of cabbage by agreement 29.04.2019 TAX Free | Y
2 | Payment for screws (01.04.19) Tax: 13.55 %           | Y
3 | For reserch by deal dated 01.01.2015 Tax free        | Y
4 | Tax payment for the may 2019                         | Y