Histogram

Distribution of a single numeric variable

Histograms show the distribution of a numeric variable by grouping values into bins and counting occurrences in each bin.

Code

SELECT Temp FROM ggsql:airquality
VISUALISE Temp AS x
DRAW histogram
LABEL
  title => 'Temperature Distribution',
  x => 'Temperature (F)',
  y => 'Count'

Explanation

• VISUALISE Temp AS x specifies the variable to bin
• DRAW histogram automatically computes bins and counts
• No y mapping is needed - ggsql computes the count automatically

Variations

Custom bin count

Control the number of bins with SETTING bins:

SELECT Temp FROM ggsql:airquality
VISUALISE Temp AS x
DRAW histogram
  SETTING bins => 15
LABEL
  title => 'Temperature Distribution (15 bins)',
  x => 'Temperature (F)',
  y => 'Count'

Custom bin width

Set explicit bin width instead of count:

SELECT Temp FROM ggsql:airquality
VISUALISE Temp AS x
DRAW histogram
  SETTING binwidth => 5
LABEL
  title => 'Temperature Distribution (5 degree bins)',
  x => 'Temperature (F)',
  y => 'Count'

Density instead of count

Use REMAPPING to show density (proportion) instead of count:

SELECT Temp FROM ggsql:airquality
VISUALISE Temp AS x
DRAW histogram
  REMAPPING density AS y
LABEL
  title => 'Temperature Density',
  x => 'Temperature (F)',
  y => 'Density'