Slugify for snowflake (dbt-labs#707)

CHANGELOG.md

@@ -11,6 +11,7 @@
 # Unreleased
 
 ## New features
+- Updated the `slugify` macro to prepend "_" to column names beginning with a number since most databases do not allow names to begin with numbers. 
 - Implemented an optional `group_by_columns` argument across many of the generic testing macros to test for properties that only pertain to group-level or are can be more rigorously conducted at the group level. Property available in `recency`, `at_least_one`, `equal_row_count`, `fewer_rows_than`, `not_constant`, `not_null_proportion`, and `sequential` tests [#633](https://github.com/dbt-labs/dbt-utils/pull/633)
 - New feature to omit the `source_column_name` column on the `union_relations` macro ([#331](https://github.com/dbt-labs/dbt-utils/issues/331), [#624](https://github.com/dbt-labs/dbt-utils/pull/624))
 - New feature to select fewer columns in `expression_is_true` ([#683](https://github.com/dbt-labs/dbt-utils/issues/683), [#686](https://github.com/dbt-labs/dbt-utils/pull/686))
@@ -58,6 +59,8 @@ models:
 - Fix to utilize dbt Core version of `escape_single_quotes` instead of version from dbt Utils ([[#689](https://github.com/dbt-labs/dbt-utils/issues/689)], [#692](https://github.com/dbt-labs/dbt-utils/pull/692))
 
 ## Contributors:
+- [@fivetran-catfritz](https://github.com/fivetran-catfritz)
+- [@crowemi](https://github.com/crowemi)
 - [@CR-Lough] (https://github.com/CR-Lough) (#706)
 - [@SimonQuvang](https://github.com/SimonQuvang) (#701)
 - [@christineberger](https://github.com/christineberger) (#624)

integration_tests/tests/jinja_helpers/test_slugify.sql

@@ -1,7 +1,9 @@
-{% if dbt_utils.slugify('!Hell0 world-hi') == 'hell0_world_hi' %}
-    {# Return 0 rows for the test to pass #}
-    select 1 as col_name {{ limit_zero() }}
-{% else %}
-    {# Return >0 rows for the test to fail #}
-    select 1 as col_name
-{% endif %}
+with comparisons as (
+  select '{{ dbt_utils.slugify("!Hell0 world-hi") }}' as output, 'hell0_world_hi' as expected
+  union all
+  select '{{ dbt_utils.slugify("0Hell0 world-hi") }}' as output, '_0hell0_world_hi' as expected
+)
+
+select * 
+from comparisons
+where output != expected

macros/jinja_helpers/slugify.sql

@@ -6,7 +6,9 @@
 {% set string = modules.re.sub('[ -]+', '_', string) %}
 {#- Only take letters, numbers, and underscores -#}
 {% set string = modules.re.sub('[^a-z0-9_]+', '', string) %}
+{#- Prepends "_" if string begins with a number -#}
+{% set string = modules.re.sub('^[0-9]', '_' + string[0], string) %}
 
 {{ return(string) }}
 
-{% endmacro %}
+{% endmacro %}