KATER__PREVIOUS_PERIOD

Family: Calendar comparisons

Syntax

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KATER__PREVIOUS_PERIOD(measure [, by => date] [, coverage => 'matching_elapsed' | 'full_period'])

Arguments

Required

Optional

Returns

A number. 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

• It works the measure out again over the source rows of the earlier period. It does not read an earlier row of the result, so a period with no row still has a value.
• The axis is a date at a grain of day, week, month, quarter or year. Left out, by is the one date in GROUP BY. With two, or none, name one with by.
• Without a date filter, a month that is not over yet compares with the whole month before it.
• A date filter on the axis needs fixed dates at both ends. A moving end, such as CURRENT_DATE, is refused.
• For the change, subtract the call from EVAL(measure). For the percent change, give EVAL(measure) and the call to KATER__PERCENT_CHANGE.
• In a query, declare it with CUSTOM_CALCULATION. As a MEASURE, it needs by.

Example

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

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SELECT
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  KATER__MONTH(orders.order_date) AS "Order Month",
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  EVAL(orders.sum__quantity) AS "Units",
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  CUSTOM_CALCULATION(
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    'previous_period__sum__quantity',
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    KATER__PREVIOUS_PERIOD(orders.sum__quantity, by => KATER__MONTH(orders.order_date))
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  ) AS "Units Month Before"
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FROM kater_dataset.orders AS orders
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WHERE
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  KATER__IS_BETWEEN(orders.order_date, DATE '2026-05-01', DATE '2026-09-30')
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GROUP BY
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  KATER__MONTH(orders.order_date)
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ORDER BY
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  1

See also

• Period comparisons
• Other functions in Calendar comparisons: KATER__SAME_PERIOD_LAST_YEAR, KATER__SAME_WEEKDAY_LAST_WEEK, KATER__PERIOD_SHIFT, KATER__PERCENT_CHANGE