Feature/add substitution condition (#43)

* add condition for sql formatting to fix error when no substitution togetehr with sql containing curly brackets was given.

* edit changelog and contributors

CHANGELOG.rst

@@ -1,6 +1,12 @@
 Development
 ***********
 
+0.3.2 (2023-09-19)
+******************
+
+- Add condition for string substitution so that empty substitutions together with sqls,
+  that contain curly brackets won't fail
+
 0.3.1 (2023-08-15)
 ******************
 

CONTRIBUTORS.rst

@@ -11,5 +11,6 @@ This is a list of the people who directly contributed to bquest in one way or an
 * `Nils Weisbach <https://github.com/ncwhh>`_
 * `Julian Werner <https://github.com/scieneers-jw>`_
 * `Jia-Jen Yang <https://github.com/jiajentw>`_
+* `Jeffrey Ungelenk <https://github.com/Depaccu>`_
 
 Special thanks goes to `Mike Czech <https://github.com/mikeczech>`_ who initiated the development of bquest!

bquest/runner.py

@@ -201,6 +201,8 @@ def run(
             sql: SQL query that is being executed in BigQuery
             source_table_definitions: source table definitions, list of BQTableDefinition
             substitutions: substitutions for the given query
+            Can't use substitutions together with sql that contains curly brackets, for example sql with regexs.
+            This leads to error when trying to substitute the regex which shouldn't be substituted.
             string_replacements: entire string replacements for the query, substitutions are placed before
             result_table_definition: result table definition
 
@@ -219,8 +221,8 @@ def run(
             if result_table_definition
             else self._create_empty_result_table("result")
         )
-
-        sql_with_substitutions = sql.format(**substitutions)
+        if substitutions:
+            sql_with_substitutions = sql.format(**substitutions)
         for key, value in string_replacements.items():
             sql_with_substitutions = sql_with_substitutions.replace(key, value)