Add percentile_cont and percentile_disc macros

integration_tests/data/sql/data_percentile.csv

@@ -0,0 +1,6 @@
+id,val
+1,10
+2,20
+3,30
+4,40
+5,50

integration_tests/models/sql/schema.yml

@@ -269,3 +269,15 @@ models:
       - assert_equal:
           actual: actual
           expected: expected
+
+  - name: test_percentile_cont
+    data_tests:
+      - assert_equal:
+          actual: actual
+          expected: expected
+
+  - name: test_percentile_disc
+    data_tests:
+      - assert_equal:
+          actual: actual
+          expected: expected

integration_tests/models/sql/test_percentile_cont.sql

@@ -0,0 +1,17 @@
+with data as (
+
+    select * from {{ ref('data_percentile') }}
+
+),
+
+calculated as (
+
+    select
+        {{ dbt_utils.percentile_cont('val', 0.5) }} as actual,
+        30 as expected
+
+    from data
+
+)
+
+select distinct actual, expected from calculated

integration_tests/models/sql/test_percentile_disc.sql

@@ -0,0 +1,17 @@
+with data as (
+
+    select * from {{ ref('data_percentile') }}
+
+),
+
+calculated as (
+
+    select
+        {{ dbt_utils.percentile_disc('val', 0.5) }} as actual,
+        30 as expected
+
+    from data
+
+)
+
+select distinct actual, expected from calculated

macros/sql/percentile.sql

@@ -0,0 +1,28 @@
+{% macro percentile_cont(column, percentile_value) -%}
+  {{ return(adapter.dispatch('percentile_cont', 'dbt_utils')(column, percentile_value)) }}
+{%- endmacro %}
+
+{% macro default__percentile_cont(column, percentile_value) -%}
+    percentile_cont({{ percentile_value }}) within group (order by {{ column }})
+{%- endmacro %}
+
+{% macro bigquery__percentile_cont(column, percentile_value) -%}
+    percentile_cont({{ column }}, {{ percentile_value }}) over()
+{%- endmacro %}
+
+
+{% macro percentile_disc(column, percentile_value) -%}
+  {{ return(adapter.dispatch('percentile_disc', 'dbt_utils')(column, percentile_value)) }}
+{%- endmacro %}
+
+{% macro default__percentile_disc(column, percentile_value) -%}
+    percentile_disc({{ percentile_value }}) within group (order by {{ column }})
+{%- endmacro %}
+
+{% macro bigquery__percentile_disc(column, percentile_value) -%}
+    percentile_disc({{ column }}, {{ percentile_value }}) over()
+{%- endmacro %}
+
+{% macro redshift__percentile_disc(column, percentile_value) -%}
+    approximate percentile_disc({{ percentile_value }}) within group (order by {{ column }})
+{%- endmacro %}