Implement charindex macro DNA-15944 [DNA-20680]

README.md

@@ -26,6 +26,7 @@ This dbt package contains macros for SQL functions to run the dbt project on mul
 
 - [Multiple databases](#Multiple-databases)
   - [as_varchar](#as_varchar-source)
+  - [charindex](#charindex-source)
   - [create_index](#create_index-source)
   - [date_from_timestamp](#date_from_timestamp-source)
   - [datediff](#datediff-source)
@@ -61,6 +62,12 @@ This macro converts a string to the data type `nvarchar(2000)` for SQL Server. U
 Usage: 
 `{{ pm_utils.as_varchar('[expression]') }}`
 
+#### charindex ([source](macros/multiple_databases/charindex.sql))
+This macro returns the starting position of the first occurrence of a string in another string. The search is not case-sensitive. If the string is not found, the function returns 0. This macro can be used to check whether a string contains another string.
+
+Usage: 
+`{{ pm_utils.charindex('[expression_to_find]', '[field]', '[start_location]') }}`
+
 #### create_index ([source](macros/multiple_databases/create_index.sql))
 This macro creates a clustered columnstore index on the current model for SQL Server. This macro should be used in a dbt post-hook.
 

macros/multiple_databases/charindex.sql

@@ -0,0 +1,21 @@
+{%- macro charindex(expression_to_find, field, start_location=None) -%}
+case
+    when len('{{ expression_to_find }}') > 0
+    then
+        {% if start_location is none -%}
+            {% if target.type == 'databricks' -%}
+                position('{{ expression_to_find }}', {{ field }})
+            {% else -%}
+                charindex('{{ expression_to_find }}', {{ field }})
+            {% endif -%}
+        {% else -%}
+            {% if target.type == 'databricks' -%}
+                position('{{ expression_to_find }}', {{ field }}, {{ start_location }})
+            {% else -%}
+                charindex('{{ expression_to_find }}', {{ field }}, {{ start_location }})
+            {% endif -%}
+        {% endif -%}
+    else
+        0
+end
+{%- endmacro -%}