String functions 🎻

Author: Sibyx

.github/workflows/tests.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.6, 3.7, 3.8, 'pypy3']
 
     steps:
     - uses: actions/checkout@v1

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.6.0 : 2020-07-23
+
+- **Feature**: `lower` function introduced
+- **Feature**: `upper` function introduced
+- **Feature**: pSQL `initcap` function introduced
+
 ## 0.5.0 : 2020-07-22
 
 - **Feature**: `QueryFactory` supporting `json`, `msgpack` and `bson`

docs/functions/initcap.md

@@ -0,0 +1,40 @@
+# InitCap
+
+## Basic information
+
+|                 |                                |
+|-----------------|--------------------------------|
+| **Object type** | `functions.InitCap`            |
+| **Since**       | 0.6.0                          |
+| **Dialects**    | `PostgreSQL`                   |
+
+
+## Object attributes
+
+| Attribute       | Accepts                                                       | Required |
+|-----------------|---------------------------------------------------------------|----------|
+| obj             | `functions.InitCap`                                           | True     |
+| property        | `properties.Property` `functions.*` `Constant` `CastOperator` | True     |
+| alias           | String                                                        | False    |
+
+## JSON format
+
+```json
+{
+  "obj": "functions.InitCap",
+  "property": {
+    "obj": "properties.Property",
+    "name": "users.name"
+  }
+}
+```
+
+## SQL
+
+```sql
+initcap(users.name)
+```
+
+## SQL reference
+
+- [PostgreSQL - String Functions and Operators](https://www.postgresql.org/docs/current/functions-string.html)

docs/functions/lower.md

@@ -0,0 +1,41 @@
+# Lower
+
+## Basic information
+
+|                 |                                |
+|-----------------|--------------------------------|
+| **Object type** | `functions.Lower`              |
+| **Since**       | 0.6.0                          |
+| **Dialects**    | `PostgreSQL` `MySQL` `MariaDB` |
+
+
+## Object attributes
+
+| Attribute       | Accepts                                                       | Required |
+|-----------------|---------------------------------------------------------------|----------|
+| obj             | `functions.Lower`                                             | True     |
+| property        | `properties.Property` `functions.*` `Constant` `CastOperator` | True     |
+| alias           | String                                                        | False    |
+
+## JSON format
+
+```json
+{
+  "obj": "functions.Lower",
+  "property": {
+    "obj": "properties.Property",
+    "name": "users.name"
+  }
+}
+```
+
+## SQL
+
+```sql
+lower(users.name)
+```
+
+## SQL reference
+
+- [PostgreSQL - String Functions and Operators](https://www.postgresql.org/docs/current/functions-string.html)
+- [MariaDB - Lower](https://mariadb.com/kb/en/lower/)

docs/functions/upper.md

@@ -0,0 +1,41 @@
+# Upper
+
+## Basic information
+
+|                 |                                |
+|-----------------|--------------------------------|
+| **Object type** | `functions.Upper`              |
+| **Since**       | 0.6.0                          |
+| **Dialects**    | `PostgreSQL` `MySQL` `MariaDB` |
+
+
+## Object attributes
+
+| Attribute       | Accepts                                                       | Required |
+|-----------------|---------------------------------------------------------------|----------|
+| obj             | `functions.Upper`                                             | True     |
+| property        | `properties.Property` `functions.*` `Constant` `CastOperator` | True     |
+| alias           | String                                                        | False    |
+
+## JSON format
+
+```json
+{
+  "obj": "functions.Upper",
+  "property": {
+    "obj": "properties.Property",
+    "name": "users.name"
+  }
+}
+```
+
+## SQL
+
+```sql
+upper(users.name)
+```
+
+## SQL reference
+
+- [PostgreSQL - String Functions and Operators](https://www.postgresql.org/docs/current/functions-string.html)
+- [MariaDB - Upper](https://mariadb.com/kb/en/upper/)

duckql/functions/__init__.py

@@ -16,6 +16,9 @@
 from .to_char import ToChar
 from .to_date import ToDate
 from .unaccent import Unaccent
+from .lower import Lower
+from .upper import Upper
+from .initcap import InitCap
 
 __all__ = [
     "Avg",
@@ -36,5 +39,8 @@
     "Now",
     "ToChar",
     "ToDate",
-    "Unaccent"
+    "Unaccent",
+    "Lower",
+    "Upper",
+    "InitCap"
 ]

duckql/functions/initcap.py

@@ -0,0 +1,22 @@
+from typing import Union
+
+from typing_extensions import Literal
+
+from .base import BaseFunction
+from ..properties import Constant
+from ..properties.property import Property
+from ..structures.cast_operator import CastOperator
+
+
+class InitCap(BaseFunction):
+    obj: Literal['functions.InitCap'] = 'functions.InitCap'
+    property: Union[Property, BaseFunction, Constant, CastOperator]
+    alias: str = None
+
+    def to_sql(self) -> str:
+        sql = f"initcap({self.property})"
+
+        if self.alias is not None:
+            sql = f"{sql} AS {self.alias}"
+
+        return sql

duckql/functions/lower.py

@@ -0,0 +1,22 @@
+from typing import Union
+
+from typing_extensions import Literal
+
+from .base import BaseFunction
+from ..properties import Constant
+from ..properties.property import Property
+from ..structures.cast_operator import CastOperator
+
+
+class Lower(BaseFunction):
+    obj: Literal['functions.Lower'] = 'functions.Lower'
+    property: Union[Property, BaseFunction, Constant, CastOperator]
+    alias: str = None
+
+    def to_sql(self) -> str:
+        sql = f"lower({self.property})"
+
+        if self.alias is not None:
+            sql = f"{sql} AS {self.alias}"
+
+        return sql

duckql/functions/tests/test_initcap.py

@@ -0,0 +1,14 @@
+from duckql.properties.property import Property
+from duckql.functions.initcap import InitCap
+
+
+def test_property():
+    my_function = InitCap(property=Property(name='users.name'))
+
+    assert str(my_function) == 'initcap(users.name)'
+
+
+def test_alias():
+    my_function = InitCap(property=Property(name='users.name'), alias='"capitalized')
+
+    assert str(my_function) == 'initcap(users.name) AS capitalized'

duckql/functions/tests/test_lower.py

@@ -0,0 +1,14 @@
+from duckql.properties.property import Property
+from duckql.functions.lower import Lower
+
+
+def test_property():
+    my_function = Lower(property=Property(name='users.name'))
+
+    assert str(my_function) == 'lower(users.name)'
+
+
+def test_alias():
+    my_function = Lower(property=Property(name='users.name'), alias='"lower_name')
+
+    assert str(my_function) == 'lower(users.name) AS lower_name'