cx_Oracle.DatabaseError：ORA-00932：不一致的数据类型：预期的 CHAR 得到了 NUMBER

Question

我正在尝试将 Python 中的用户输入传递到 SQL 以按日期范围过滤数据。我在 SQL 中没有遇到任何问题，例如：

SELECT * from trades
WHERE share_id = 1
AND broker_id =1
AND transaction_time >= TO_DATE('2020-11-01','YYYY-MM-DD')
AND transaction_time <= TO_DATE('2020-12-01','YYYY-MM-DD');

我在 Python 中也没有遇到问题，只有 transaction_time 部分，例如：

from_date_val = input("Enter from-date (YYYY-MM-DD) to search, enter nothing to skip: ")
to_date_val = input("Enter to-date (YYYY-MM-DD) to search, enter nothing to skip: ")

cursor.execute("""SELECT * FROM trades WHERE 1=1
                  AND transaction_time >= CASE WHEN :from_date IS NOT NULL
                  THEN TO_DATE(:from_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END
                  AND transaction_time <= CASE WHEN :to_date IS NOT NULL
                  THEN TO_DATE(:to_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END""", 
                  from_date = from_date_val, 
                  to_date = to_date_val)

但如果我这样做：

share_id_val = input("Enter share id to search, enter nothing to skip: ")
broker_id_val = input("Enter broker id to search, enter nothing to skip: ")
from_date_val = input("Enter from-date (YYYY-MM-DD) to search, enter nothing to skip: ")
to_date_val = input("Enter to-date (YYYY-MM-DD) to search, enter nothing to skip: ")

cursor.execute("""SELECT * FROM trades WHERE 1=1
                  AND share_id = CASE WHEN :share_id IS NOT NULL 
                  THEN :share_id ELSE share_id END
                  AND broker_id = CASE WHEN :broker_id IS NOT NULL 
                  THEN :broker_id ELSE broker_id END
                  AND transaction_time >= CASE WHEN :from_date IS NOT NULL
                  THEN TO_DATE(:from_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END
                  AND transaction_time <= CASE WHEN :to_date IS NOT NULL
                  THEN TO_DATE(:to_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END""", 
                  share_id = share_id_val, 
                  broker_id = broker_id_val,
                  from_date = from_date_val, 
                  to_date = to_date_val)

它返回：cx_Oracle.DatabaseError:

ORA-00932：不一致的数据类型：预期的 CHAR 得到了 NUMBER。

在from_date = from_date_val 和to_date = to_date_val 的行上。

这真的让我发疯了几个小时，有人可以帮我解决这个问题吗？提前致谢。

Answer 1

share_id 和 broker_id 是 NUMBER 数据类型；但是，在 Python 中，input 函数返回一个字符串，您将其直接作为绑定变量传递，然后：

CASE WHEN :share_id IS NOT NULL THEN :share_id ELSE share_id END

:share_id 绑定变量将是字符串数据类型，share_id 列具有NUMBER 数据类型；这会导致您的错误：

ORA-00932: inconsistent datatypes: expected CHAR got NUMBER.

要修复它，您需要将字符串输入值转换为数字。您可以在 Python 中使用int() 进行转换：

cursor.execute("""SELECT * FROM trades WHERE 1=1
                  AND share_id = CASE WHEN :share_id IS NOT NULL 
                  THEN :share_id ELSE share_id END
                  AND broker_id = CASE WHEN :broker_id IS NOT NULL 
                  THEN :broker_id ELSE broker_id END
                  AND transaction_time >= CASE WHEN :from_date IS NOT NULL
                  THEN TO_DATE(:from_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END
                  AND transaction_time <= CASE WHEN :to_date IS NOT NULL
                  THEN TO_DATE(:to_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END""", 
                  share_id = int(share_id_val), 
                  broker_id = int(broker_id_val),
                  from_date = from_date_val, 
                  to_date = to_date_val)

或者在SQL语句中使用TO_NUMBER：

cursor.execute("""SELECT * FROM trades WHERE 1=1
                  AND share_id = CASE WHEN :share_id IS NOT NULL 
                  THEN TO_NUMBER(:share_id) ELSE share_id END
                  AND broker_id = CASE WHEN :broker_id IS NOT NULL 
                  THEN TO_NUMBER(:broker_id) ELSE broker_id END
                  AND transaction_time >= CASE WHEN :from_date IS NOT NULL
                  THEN TO_DATE(:from_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END
                  AND transaction_time <= CASE WHEN :to_date IS NOT NULL
                  THEN TO_DATE(:to_date, 'YYYY-MM-DD') 
                  ELSE transaction_time END""", 
                  share_id = share_id_val, 
                  broker_id = broker_id_val,
                  from_date = from_date_val, 
                  to_date = to_date_val)