NodeJS Mysql Query with multiple fields in where clause - mysql

Question

I'm working with MySQL for a while and also built an API in NodeJS including mySQL for work
Basically i need a query like "SELECT * FROM table WHERE fieldA=varA AND/OR fieldB=valB"
I'm using "mysql.format(sql, args)" to format my query, so i'm using ? and ?? in my Queries.
I would like to write a basic query, that i could use and feed all the needed fields and values
I tried the following ways
-> "SELECT * FROM table WHERE ?" with "{fieldA: varA, fieldB: varB}" as replacement for ?
that leads to "SELECT * FROM table WHERE fieldA='varA', fieldB='varB'"
-> "SELECT * FROM table WHERE ?? = ?" with "['fieldA', 'fieldB']" and "['varA', 'varB']" as replacements
what leads to "SELECT * FROM table WHERE fieldA, fieldB = 'varA', 'varB'"
For now i "only" need 2 different fields, so i could add fixed "fieldA=? AND/OR fieldB=?" and fill only the values. But i would like a dynamic way and give all the fields i could need in it and also if i use AND or OR in combining.
I didn't find anything like this in the documentation, maybe somebody here had stumbled upon before.
Or might it be the only solution to dynamically add some "AND/OR ?? = ?" to the query and fill the arguments array with fieldName, values one after the other?

Answer 1

Consider theses are the fields that you need to build your dynamic query string.
var fields = [{fieldName:"A",value:"one",operator:"AND"},{fieldName:"B",value:"two",operator:""}];
Now try building your query string with that array. For now I have considered only two fields but you can add as per your needs.
var fields = [{fieldName:"A",value:"one",operator:"AND"},{fieldName:"B",value:"two",operator:""}];
var query = "SELECT * FROM table WHERE ";
fields.forEach((f)=>{
query=query+`${f.fieldName} = ${f.value} `
if(f.operator!="") query=query+f.operator+" "
})
console.log(query)

Answer 2

I have built a method for this now, with hints from Ameers answer. It will generate a query like
SELECT * FROM ?? WHERE ??=? AND/OR ??=? AND/OR ??=?
and then will add the fieldName and values to the arguments array for mysql.format
var fieldValues = [
{ field: 'command', value: command.command, operator: 'OR' },
{ field: 'alias', value: command.command, operator: 'OR' }
];
exists(fieldValues) {
let query = 'SELECT * FROM ??';
let args = ['tablename'];
for (let i = 0; i < fieldValues.length; i++) {
let operator = i == 0 ? 'WHERE' : fieldValues[i].operator;
query += ` ${operator} ?? = ?`;
args.push(fieldValues[i].field);
args.push(fieldValues[i].value);
}
return mysql.query(query, args);
}
mysql.query() here is my wrapper around mysql.connection.query and using promises
Maybe there is a better builtin method, but i didn't find one yet and this way i can still use the builtin mysql-formatter function.

Answer 3

Consider,
that you have fields in DB like first_name, last_name, personal_email, work_email and office_name.
and you want to get all result matching with search fields.
i.e. let search = req.query.search.
It will become easy with ORM like Objection.js
So the query will be like this using objection.js
if (search) {
table_name.where('column_name.last_name', 'like', `%${search}%`)
.orWhere('column_name.first_name', 'like', `%${search}%`)
.orWhere('column_name.personal_email', 'like', `%${search}%`)
.orWhere('column_name.work_email', 'like', `%${search}%`)
.orWhere('column_name.office_name', 'like', `%${search}%`)
}
Note: This code is in nodejs and you can also use table_name you can also add model_name.