Filters and parameters

Give readers controls for dates and values, set fixed filters on a report or page, let charts filter each other, and add parameters that formulas read.

A report narrows its data in five ways. This page covers each one and when to use it. Try the small report below: pick a filter, then click a bar and watch the other charts follow.

Filters, scorecards and charts that filter each other, over sample data.

Way	Who sets it	Use it for
Filter control	Readers	Choices readers make, such as a date range or a region
Report or page filter	You, in the builder	Narrowing what the page shows, with no control for readers, such as one product line. Locked, it also limits what a public link or embed can read
Cross-filter	Readers, by clicking a chart	Following a thread from one chart to the rest of the page
Parameter	Readers	A value formulas read, such as a target
Locked filter	You, with Lock on a report or page filter, or your server, in a signed token	Limiting what a public link or embed can read, out of the reader's reach

Filter controls

Choose Add, then Filter control.
Pick the dataset and the field in Filters the field.
Choose how readers set it in Readers set it with.

Type	For	Readers get
Date range with presets	Dates	A calendar and a list of presets
Relative dates	Dates	Presets only
Single select	Any field	One value from a list
Multi-select with search	Any field	Several values, with a search box
Text search	Text	A box that matches as they type
Number range	Numbers	A low and a high value on a slider
Toggle	Any field	On keeps rows with one value, off keeps all
Top N	Groupings	The top groups by a measure

In the inspector:

Reaches sets This page or Every page. Only these elements narrows it further.
A control also reaches elements over other datasets, by field name. A control on region filters every element in scope whose dataset has a region field, and skips the rest.
Choices follow makes one control depend on another, such as a country before its cities.
Starts with is the value readers begin on, and they can change it.
Most values listed caps a select's list, 500 by default. Past it, typing searches the dataset.

Date ranges

Date controls offer the presets you pick under Presets, in the order you pick them. Last N days, weeks and months are always offered.

The picker readers get, and the dates a preset means today.

Presets are worked out each time in the report's time zone. Last N days ends yesterday, last N weeks or months ends with the last whole week or month, a "to date" range runs through today, and fiscal presets follow your organization's fiscal year. See Dates and time zones.

Report and page filters

These are conditions you set that readers don't get a control for. With nothing selected, add one under Report filters, which reach every page, or Page filters, which reach this page and add to the report's. Each reaches every element whose dataset has the field.

Cross-filtering

Clicking a mark on a chart filters the other elements on the page by what was clicked. It's on by default. Turn it off for one chart with Clicking filters the page, in its Interactions section. Charts with no one value behind a mark, such as scatter plots, Gantt charts, gauges and point maps, turn that off themselves.

What a reader changes shows above the page, each with a way back. Filtered by names what they clicked, Clear filters lets go of them all, and Reset returns the report to how you left it.

To open another page instead, set Clicking opens to a page. That's drill-through: the page opens filtered by the clicked values, and Back returns. Exploring a chart further is in Exploring charts.

Parameters

A parameter is a value readers set that isn't a filter on a field, such as a growth target. Formulas read it as @name:

SUM([Revenue]) * (1 + @growth_target)

With nothing selected, press + beside Parameters. Set its Name in formulas, Label and Type, then what it starts at.
Choose Add, then Parameter control, to put it on a page. Sets picks the parameter and Looks like picks the control.
On the dataset, give a parameter the same name and use @name in a calculated field. The report's value takes its place, and without one the dataset's default applies.

Type	Values	Formulas get
Number	A number, with optional lowest, highest, step and choices	The number
Text	Text, with optional choices	The text
On or off	True or false	The value
Date	One day	The day
Date range	A range of days	`@name_start` and `@name_end`, as dates
List of values	Several values from a list	The picked values, joined by commas

Text can show a parameter's value in a sentence too. See Text, images and live values.

Locked filters

A locked filter is one a reader can't change or get around. Halo adds it on the server to every query that reaches its dataset, so it holds even for someone calling the API. There are two kinds.

On the report or page. Turn on Lock on a report or page filter. It applies to public links, embeds, and PDFs and snapshots made from the published report.
In a signed token. Your server puts filters in a signed embed's token. A control on a field the token locks shows its value with a lock instead of a picker, and locked filters no control shows are listed above the report.

If the report and a token both name a field, both apply, so a row has to pass both. A token can only narrow what the report allows.

Members signed in to Halo Data aren't limited by locked filters, only by their access and row policies. To vary what each person can read, use a row policy: a locked filter is the same for everyone on the link.

What a locked filter reaches

The filter says under its name which it does:

It says	It limits
Only and a dataset's name	That dataset
Every dataset with the field	Each dataset with that field. A dataset without the field isn't limited by it

A page's locked filter limits the datasets drawn on that page, and a query doesn't say which page it's for. So that dataset can't be used on any other page.

When it can't be enforced

Halo won't publish a locked filter that wouldn't hold, and requesting approval or scheduling refuses the same way. The Publish dialog says Couldn't publish and which filter it is:

It says	What to do
The locked filter on "…" on page "…" can't be enforced, because its dataset is also used outside that page	Lock it on the report instead, or keep that dataset to this page
Its locked filter on "…" matches no field in the datasets it can reach, so it wouldn't limit anything	Unlock it, or filter on a field they have

If a dataset later loses the field, so that the filter fits nothing left in the report, the link stops showing data rather than showing too much, and readers see "This report can't be shown right now." Unlock the filter or fix the field, and the link works again.

On a report with editions, a filter's preset dates read as of the period's last day. Turning on Edition readers see only the published figures stops readers changing filters at all.

In Halo Data, a reader's filters and choices live in the page's address. The report's views menu has Save this view…, which only you see, Manage views… to bring a saved view up to date, rename it or delete it, and Copy link to this view, which opens the report filtered the same way for anyone with access to it. Name in links on a control sets how it reads in that address.

A public link keeps a reader's filters in its address too, so its Copy link shares the report as it looks. See Send a filtered view. An embed's host page can set filters with the element's filter API.