PostgreSQL jdbc prepared statement 问号?占位符 如何转义

作者

digoal

日期

2020-11-24

标签

PostgreSQL , jdbc , prepared statement

背景

PostgreSQL jdbc prepared statement 问号?占位符 如何转义?

例如阿里云pase向量插件, 用于图像识别, 有一个向量计算操作符: <?> 带有问题, 可能被认为是变量占位符.

```

The error may exist in file [/Users/BaoHang/Code/Project/Coding/Java/iotx-ai-business/iotx-ai-business-dal/target/classes/mybatis/postgresql/DataUserFaceMapper.xml]

The error may involve defaultParameterMap

The error occurred while setting parameters

SQL: select id, xxx, xxx, xxx, face_id, xxx <?> ? ::pase as face_confidence, xxx, xxx from xxx where xxx = ? and xxx = ? order by xxx <?> ? ::pase limit 5

Cause: org.postgresql.util.PSQLException: 未设定参数值 5 的内容。

; 未设定参数值 5 的内容。; nested exception is org.postgresql.util.PSQLException: 未设定参数值 5 的内容。
```

用两个连续问号可以转义

https://jdbc.postgresql.org/documentation/head/statement.html

In JDBC, the question mark (?) is the placeholder for the positional parameters of a PreparedStatement. There are, however, a number of PostgreSQL operators that contain a question mark. To keep such question marks in a SQL statement from being interpreted as positional parameters, use two question marks (??) as escape sequence. You can also use this escape sequence in a Statement, but that is not required. Specifically only in a Statement a single (?) can be used as an operator.

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