英文:
escape % Wildcard in prepared statement
问题
以下是翻译好的内容：
以下代码返回一个错误：
stmt, err := DBCon.Prepare("SELECT * FROM item WHERE market_hash_name LIKE '%?%' ")
handle_error(err)
res, err := stmt.Query(market_hash_name)
错误信息为：
2022/07/09 19:57:56 http: panic serving <ip> sql: expected 0 arguments, got 1
以下语句是正确的：
stmt, err := DBCon.Prepare("SELECT * FROM item WHERE market_hash_name LIKE ? ")
如何转义百分号（%）符号？
英文:
The following code returns an error:
stmt, err := DBCon.Prepare("SELECT * FROM item WHERE market_hash_name LIKE '%?%' ")
handle_error(err)
res, err := stmt.Query(market_hash_name)
the error:
2022/07/09 19:57:56 http: panic serving <ip> sql: expected 0 arguments, got 1
this statement works:
stmt, err := DBCon.Prepare("SELECT * FROM item WHERE market_hash_name LIKE ? ")
How can I escape the %sign?
答案1
得分: 2
如何转义百分号（%）？
问题不在于百分号，问题在于?位于字符串字面量中，这使得它成为一个字面上的问号，而不是参数占位符。由于语句不将字面上的问号识别为参数占位符，它期望没有参数，这就是为什么错误消息显示为“expected 0 arguments”。
要将百分号（%）添加到参数中，你至少有两个选项：
- 将百分号（%）添加到Go参数
market_hash_name中，例如：
stmt.Query("%" + market_hash_name + "%")
- 使用SQL字符串将百分号（%）与
?连接起来，例如：
CONCAT('%', ?, '%')
英文:
> How can I escape the %sign?
The problem is not the percent sign, the problem is that ? is inside a string literal, which makes it a literal question mark and not a parameter placeholder. And because the statement does not recognize the literal question mark as a parameter placeholder it expects NO arguments, which is why the error says: expected 0 arguments.
To add % to the argument you have at least two options:
- Add the percent signs to the Go argument
market_hash_name, e.g.
stmt.Query("%"+market_hash_name+"%")
- Concatenate the percent signs to the
?in the SQL string with
CONCAT('%', ?, '%')
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