Skip to main content
DocumentationLibraryReference
On this page

Kater SQL Functions Windows

KATER__FIRST_VALUE

The value on the first row of its partition, in the OVER's order.

Family: Windows

Syntax 

KATER__FIRST_VALUE(field) OVER ([PARTITION BY ...] ORDER BY ...)

Arguments

ArgumentDescription
fieldThe value it reads on each row: a field, or a measure, such as orders.sum__amount.

Returns

A value of the field’s own type. The field menu writes the @format of the field it reads beside it, or @format number(2) where that field has none and can have decimals.

Usage notes

  • Write OVER (ORDER BY ...), and add PARTITION BY to start again for each group. It writes its own frame, so its OVER takes no ROWS or RANGE.
  • It reads the whole partition, so each row gets the same first value.

Example

This Sandbox query reads the sample shop’s orders. The table shows the rows that Kater gave.

SELECT
  orders.order_month AS "Order Month",
  EVAL(orders.sum__quantity) AS "Units",
  CUSTOM_CALCULATION(
    'first_value__sum__quantity',
    KATER__FIRST_VALUE(orders.sum__quantity) OVER (ORDER BY orders.order_month)
  ) AS "Units First Month"
FROM kater_dataset.orders AS orders
WHERE
  KATER__IS_ON_OR_AFTER(orders.order_date, DATE '2026-05-01')
GROUP BY
  orders.order_month
ORDER BY
  1
Order MonthUnitsUnits First Month
2026-05-01441441
2026-06-01403441
2026-07-01438441
2026-08-01454441
2026-09-01442441

Compiles to 

FIRST_VALUE(orders.sum__quantity) OVER (
  ORDER BY orders.order_month
  ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
)
FIRST_VALUE(orders.sum__quantity) OVER (ORDER BY orders.order_month)

See also