如何使用 Postges 和 Knex.js 查询特定月份的日期字段

Question

Im setting up a new date query using Knex.js and Postgres. I need to return all the rows for a specific month from the table.

This is for a simple app API. Ive managed to return all the fields from the table that I want but don't know how to query the date field for the specific month. Im using Knex.js as my query builder and have the following:

db('table').select() 
.where('Month(date)', '=', 0  ); //this field where I am lost, 

the sql I think will do the job is: EXTRACT(MONTH FROM dateColumn::date) = 1

I get an error at the moment. But I am expecting to query to return all the date fields that are in the month of January. I know that I could use the .whereRaw() field but Im not 100% sure how to use this either as the documentation does not provide any use cases for date fields.

For reference the column date that I want to query is of format date

Answer 1

I managed to get this to work by using the .whereRaw() API of knex.

.andWhereRaw(`EXTRACT(MONTH FROM dateColumn::date) = ?`, [monthVariable])

Im not totally sure why, but it only worked with the ::date suffix to my dateColumn . This will cast my dateColumn to postgres dateType. The confusing part is that the dateColumn was already of type date .

Answer 2

也许这个：

db('table').where(db.raw('EXTRACT(MONTH FROM ??::date)', ['dateColumn']), 0)