通过 axios 帖子将 null 值发送到 sql

Question

I have a very simple question. I want to send null value to MySql server using axios.post method. The value is defined as an int in the sql table. I have tried passing null but nothing happens. I have also tried passing '' but I end up with 0. I validated that any random int will work by passing random integers with no problem. I really need to make it null though. How can I do this? This sends nothing...

    axios.post("http://localhost:3001/api/update-air", 
    {airValue: null}).then(() => {
        alert("Successfull")
    })

This sends 0...

    axios.post("http://localhost:3001/api/update-air", 
    {airValue: ''}).then(() => {
        alert("Successfull")
    })

This sends 100...

    axios.post("http://localhost:3001/api/update-air", 
    {airValue: 100}).then(() => {
        alert("Successfull")
    })

I need it to change an int back to null by literally sending null as a value.

server side code...

app.post("/api/update-air", (req, res) => {
    const airValue = req.body.airValue;
    const sqlUpdateAir = "UPDATE user SET airValue=(?) WHERE uid='j' ";
    db.query(sqlUpdateAir, (airValue), (err, result)=>{
        console.log(airValue);
    })

Answer 1

null needs to be wrapped in an array [] when queried. so replace this...

db.query(sqlUpdateAir, null, (err, result)=>{
    console.log(airValue);
})

with this...

db.query(sqlUpdateAir, [null], (err, result)=>{
    console.log(airValue);
})