Common issues with Postgres in Duaer

Fill an IN list with query parameters

In Execute Query, set Options > Query Parameters to an expression that returns an array, such as {{ $json.sizes }}. From node version 2.5, Duaer expands the array into $1, $2, and so on. Generate the IN placeholders from the array length:

SELECT color, size FROM shirts
WHERE size IN ({{ $json.sizes.map((_, i) => '$' + (i + 1)).join(', ') }});

Timestamps and time zones

• Store and pass times in UTC.
• Set Timezone in the digital organization settings. Self-hosted instances set the default with GENERIC_TIMEZONE.
• Pass dates between nodes as ISO 8601 strings and convert with Date & Time when needed.

DATE columns come back as ISO datetime strings

From Postgres node version 2.7, DATE columns come back as-is, such as 2025-12-25. Older versions turn them into ISO datetimes, which the time zone can shift to the previous day. Add the node again to get the current version, or format in the query:

SELECT TO_CHAR(date_col, 'YYYY-MM-DD') AS date_col FROM my_table;