Need help with query fragments to derive WHERE conditions

[alpozcan]

Just started using this library and while I'm having good results with simpler queries, I wasn't able to get the below code working - when there are predicates present, no rows are returned:

const predicates: string[] = [];
...
predicates.push(`root_note = '${rootNote}'`); // rootNote is 'B'
predicates.push(`quality = '${quality}'`); // quality is 'Major'
...
const sql_predicate = predicates.length > 0 ? sql`WHERE ${predicates.join(' AND ')}` : sql``; // DOESN'T WORK
const query = sql`SELECT * FROM chords ${sql_predicate} LIMIT ${MAXIMUM_CHORDS_RETURNED}`
const chords = await query;

It works with this literal string:

const sql_predicate = sql`WHERE quality = 'Major' AND root_note = 'B'`; // WORKS

Debug log line for the non-working query:

 'SELECT * FROM chords WHERE $1 LIMIT $2' with params [root_note = 'B' AND quality = 'Major',100]

and the working one:

 'SELECT * FROM chords WHERE quality = 'Major' AND root_note = 'B' LIMIT $1' with params [100]

I have gone through the README, including the sections Building queries and Quick primer on interpolation and still couldn't get this working. I'd appreciate your help!

[alpozcan]

The below is the query log from postgres for the bad query showing the first parameter as 'f'

postgres-1  | 2025-01-02 06:06:09.849 UTC [32] LOG:  execute o537t09wnn2: SELECT * FROM chords WHERE $1 LIMIT $2
postgres-1  | 2025-01-02 06:06:09.849 UTC [32] DETAIL:  Parameters: $1 = 'f', $2 = '100'

[alpozcan]

solved it like this:

let query = sql`SELECT * FROM chords WHERE true`
...
query = sql`${query} AND tuning = ${tuning}`
...
query = sql`${query} LIMIT ${MAXIMUM_CHORDS_RETURNED}`
const chords = await query;

[alpozcan]

hopefully the above approach is injection proof