nodejs中的变量sqlite3查询

Question

I'm building a simple form using node.js that asks for the things you'd expect: - First Name - Last Name - Address

and doing a query against a sqlite3 database with fields named firstName, lastName, address. I would like to mix and match queries, though — you can search for just lastName OR firstName along with lastName OR lastName with portion of street address, etc.

Writing separate queries for each case would be annoying, but I'm not sure how else to do it. In code, the following works if I enter first name or last name:

db.serialize(function() {
   db.each("SELECT rowid AS id, lastName, firstName FROM county WHERE firstName = ? OR lastName = ?", firstName, lastName, function(err, row) {
   console.log(row.id + ": " + row.firstName + ' ' + row.lastName);  
   }
}

but, if I enter first name and last name, I want that to be AND instead of only return rows where both match. If I do an AND in that clause, it returns nothing if I leave one of the fields blank.

Am I just missing a trick in constructing my query?

Thanks!

Answer 1

I think it's best to implement this in code. Something like this:

var sqlite3 = require('sqlite3').verbose(),
    db = new sqlite3.Database('peeps.db');

var runQuery = function(request) {
    var select = 'select rowid AS id, firstName, lastName from country where ',
        query,
        params = []; 

    if (request.first && request.last) {
        query = select + "firstName=? and lastName=?"
        params.push( request.first, request.last );
    } else if (request.first) {
        query = select + "firstName=?"
        params.push( request.first );
    } else if (request.last) {
        query = select + "lastName=?"
        params.push( request.last );
    }   

    if (request.address) {
        params.push( request.address );

        if (!query) {
            query = select + " address like ?"; 
        } else {
            query = query + " and address like ?"; 
        }   
    }   

    db.each( query, params, function(err, row) {
        console.log( 'id:', row.id, row.firstName, row.lastName );
    }); 
};

var createTestData = function() {

    var stmt = db.prepare('insert into country values (?, ?, ?)');

    stmt.run('john', 'smith', '123 state street');
    stmt.run('jane', 'doe', '400 doe street');
    stmt.run('jeff', 'lebowski', 'dude ave, dudeville');

    stmt.finalize();
};

db.serialize(function() {
    db.run('create table if not exists country( firstName text, lastName text, address text )');
    // createTestData();

    var searches = [ 
        { first:'john', last:'smith' },
        { first:'jane' },
        { last:'lebowski' },
        { address:'%street%' }
    ];  

    searches.forEach(function(request) {
        runQuery( request );
    }); 
});

db.close();

This isn't as object-oriented as I would like but it demonstrates how to construct SQL statements for various query parameters...