Oracle 1722遇到解决不了的异常（oracle 1722）

Oracle 1722 is a common error message encountered by Oracle database users. This error message indicates a flure to convert a character string to a number. The error code is associated with the ORA-01722 error message in the Oracle database system. The error is caused by garbage data that cannot be converted into a numeric value.

To understand this error, let us consider an example of an SQL query that is trying to convert a character string into a numeric value:

“`sql

SELECT * FROM employees WHERE salary> ‘100000’;

In the example above, the SQL query is trying to retrieve data from the employees table where the salary is greater than '100000'. This query will return the Oracle 1722 error. This is because the salary column in the employees table is defined as a numeric data type. Therefore, if you try to compare it with a string, the database engine will fl to interpret it as a number.

The solution to this issue is to ensure that the data type of the value used in the query is the same as the data type of the column you are trying to query. In our example, we can resolve the issue as follows:

```sql
SELECT * FROM employees WHERE salary> 100000;

In the query above, we have removed the quotes around the value ‘100000’, thereby making it a numeric value.

Another common cause of the Oracle 1722 error is when you try to convert a character string to a date or timestamp data type, where the character string does not conform to the required date format. In such cases, you can use the TO_DATE or TO_TIMESTAMP function to convert the character string into the desired data type.

“`sql

SELECT * FROM orders WHERE order_date = TO_DATE(‘20210101’, ‘YYYYMMDD’);

In the example above, the SQL query is trying to retrieve orders that were placed on January 1, 2021. The TO_DATE function is used to convert the string '20210101' into a date value that can be compared with the order_date column in the orders table.

In conclusion, the Oracle 1722 error is a common issue that can occur when trying to convert a character string to a numeric or date data type. To resolve this issue, you need to ensure that the data types used in the query match the data types of the columns or variables being queried. Additionally, you can use the appropriate conversion functions, such as TO_DATE and TO_TIMESTAMP, to convert the character strings into the required data type.