无法使用参数确定 SQL Like 运算符中的数据类型

Question

I'm trying to write a "select" with a parameter inside "like" operator. This is my code:

val result = connection.queryWithParamsAwait(
    "select * from users where username like '%?%'",
    jsonArrayOf(query)
)

But I'm getting this error:

could not determine data type of parameter $1

I suspect it is caused by the quotes, so I have also tried this:

val result = conn.queryWithParamsAwait(
    "select * from users where username like ?",
    jsonArrayOf("\'%$query%\'")
)

It doesn't crash but returns no results, and it should.

I'm using this client: https://github.com/vert-x3/vertx-mysql-postgresql-client

Answer 1

连接通配符和参数：

like '%' || ? || '%'

Answer 2

You might find that regular expressions are more convenient:

where username ~ ?

A regular expression matches anywhere in the string, so you don't need wildcards for the beginning and end.

This is fine if ? only consists of digits and letters -- that is, if it doesn't have special regular expression characters. However, it might be a feature that you have the power of regular expressions.