javascript - node.js - 从 mysql 查询中调用 javascript 变量

Question

我正在尝试从 mySQL 查询中调用 javascript 变量。这些行在 node.js 环境中执行，使用语法 [node (filename)]。我知道我可以分两步执行此查询，首先查询 min_value 的值，然后查询 max_value。

请求可以在一个 mySQL 查询中执行吗？

最好我希望保留 vanilla js 和 mySQL 的代码结构，而不添加特定于 node.js 的命令，也不需要加载额外的包。

Javascript 变量:

let min_value = 100;
let max_value = 300;

这个有效:

sql = `
 SELECT
   acronym,
   salaries
 FROM 
   employees
 WHERE
   salaries BETWEEN 100 and 300
ORDER BY acronym;
`;

这不起作用:

sql = `
 SELECT
   acronym,
   salaries
 FROM 
   employees
 WHERE
   salaries BETWEEN ($min_value) and ($max_value)
ORDER BY acronym;
`;

Answer 1

尝试使用 Template Literals ，使用 ${variable} 占位符语法:

let min_value = 100;
let max_value = 300;
let sql1 = `
 SELECT
   acronym,
   salaries
 FROM 
   employees
 WHERE
   salaries BETWEEN (${min_value}) and (${max_value})
ORDER BY acronym;
`;

let sql2 = `
 SELECT
   acronym,
   salaries
 FROM 
   employees
 WHERE
   salaries BETWEEN ${min_value} and ${max_value}
ORDER BY acronym;
`;

console.log(sql1);
console.log(sql2);