Postgres ExtendedInstall

Summary

Check if a specific column's value in a row matching given conditions within a specified schema and table has changed compared to an expected value.

Inputs

• Schema (required) — The schema containing the table to check.
• Table (required) — The table in which to look for the row.
• Must Match — Whether the row must satisfy all conditions ('allConditions') or any condition ('anyCondition'). Defaults to 'allConditions'.
• Conditions (required) — One or more column/operator/value conditions used to identify the target row.
• Watch Column (required) — The specific column in the matched row whose value will be checked for changes.
• Expected Value (required) — The value expected to still be held by the watch column, typically from a previous run, specified via expression or static value.

Output shape

a list of items corresponding to input items where the watch column's current value differs from the expected value

Each output item retains the original input data, enriched with 'currentValue' (the actual current value in the database) and 'expectedValue' fields in its JSON data. Items without matching rows or with errors either throw errors or, if 'continue on fail' is enabled, include an error object. Only items with changed values are output.

Examples

Example 1: Detecting a change in a user's status column after applying filter conditions

Set Schema to 'public', Table to the user's table name, Conditions to identify the user row (e.g., user ID equals a specific value), Watch Column to 'status', and Expected Value to the known previous status value (e.g., '{{ $JSON.status }}'). The operation outputs items only when the current 'status' value differs from the expected.

Links

• n8n community nodes installation guide