@directus/api/dist/database/helpers/schema/dialects/postgres.js

Directus is a real-time API and App dashboard for managing SQL database content

import { useEnv } from '@directus/env';
import { getDefaultIndexName } from '../../../../utils/get-default-index-name.js';
import { SchemaHelper } from '../types.js';
const env = useEnv();
export class SchemaHelperPostgres extends SchemaHelper {
    generateIndexName(type, collection, fields) {
        return getDefaultIndexName(type, collection, fields, { maxLength: 63 });
    }
    async getDatabaseSize() {
        try {
            const result = await this.knex.select(this.knex.raw(`pg_database_size(?) as size;`, [env['DB_DATABASE']]));
            return result[0]?.['size'] ? Number(result[0]?.['size']) : null;
        }
        catch {
            return null;
        }
    }
    addInnerSortFieldsToGroupBy(groupByFields, sortRecords, hasRelationalSort) {
        if (hasRelationalSort) {
            /*
            Postgres only requires selected columns that are not functionally dependent on the primary key to be
            included in the GROUP BY clause. Since the results are already grouped by the primary key, we don't need to
            always include the sort columns in the GROUP BY but only if there is a relational sort involved, eg.
            a sort column that comes from a related M2O relation.

            > When GROUP BY is present, or any aggregate functions are present, it is not valid for the SELECT list
              expressions to refer to ungrouped columns except within aggregate functions or when the ungrouped column is
              functionally dependent on the grouped columns, since there would otherwise be more than one possible value to
              return for an ungrouped column.
            https://www.postgresql.org/docs/current/sql-select.html

            Postgres allows aliases to be used in the GROUP BY clause

            > In strict SQL, GROUP BY can only group by columns of the source table but PostgreSQL extends this to also allow
              GROUP BY to group by columns in the select list.
      https://www.postgresql.org/docs/16/queries-table-expressions.html#QUERIES-GROUP
             */
            groupByFields.push(...sortRecords.map(({ alias }) => alias));
        }
    }
}