feat: add function Lower & Upper (#231)

* feat: add function Lower & Upper

* chore: codefmt

---------

Co-authored-by: NANASE <wszhds@gmail.com>

Author: wszhdshys

src/db.rs

@@ -6,7 +6,9 @@ use crate::expression::function::scala::ScalarFunctionImpl;
 use crate::expression::function::table::TableFunctionImpl;
 use crate::expression::function::FunctionSummary;
 use crate::function::current_date::CurrentDate;
+use crate::function::lower::Lower;
 use crate::function::numbers::Numbers;
+use crate::function::upper::Upper;
 use crate::optimizer::heuristic::batch::HepBatchStrategy;
 use crate::optimizer::heuristic::optimizer::HepOptimizer;
 use crate::optimizer::rule::implementation::ImplementationRuleImpl;
@@ -49,6 +51,8 @@ impl DataBaseBuilder {
             table_functions: Default::default(),
         };
         builder = builder.register_scala_function(CurrentDate::new());
+        builder = builder.register_scala_function(Lower::new());
+        builder = builder.register_scala_function(Upper::new());
         builder = builder.register_table_function(Numbers::new());
         builder
     }

src/function/lower.rs

@@ -0,0 +1,71 @@
+use crate::catalog::ColumnRef;
+use crate::errors::DatabaseError;
+use crate::expression::function::scala::FuncMonotonicity;
+use crate::expression::function::scala::ScalarFunctionImpl;
+use crate::expression::function::FunctionSummary;
+use crate::expression::ScalarExpression;
+use crate::types::tuple::Tuple;
+use crate::types::value::DataValue;
+use crate::types::LogicalType;
+use serde::Deserialize;
+use serde::Serialize;
+use sqlparser::ast::CharLengthUnits;
+use std::sync::Arc;
+
+#[derive(Debug, Serialize, Deserialize)]
+pub(crate) struct Lower {
+    summary: FunctionSummary,
+}
+
+impl Lower {
+    #[allow(unused_mut)]
+    pub(crate) fn new() -> Arc<Self> {
+        let function_name = "lower".to_lowercase();
+        let arg_types = vec![LogicalType::Varchar(None, CharLengthUnits::Characters)];
+        Arc::new(Self {
+            summary: FunctionSummary {
+                name: function_name,
+                arg_types,
+            },
+        })
+    }
+}
+
+#[typetag::serde]
+impl ScalarFunctionImpl for Lower {
+    #[allow(unused_variables, clippy::redundant_closure_call)]
+    fn eval(
+        &self,
+        exprs: &[ScalarExpression],
+        tuples: &Tuple,
+        columns: &[ColumnRef],
+    ) -> Result<DataValue, DatabaseError> {
+        let value = exprs[0].eval(tuples, columns)?;
+        let mut value = DataValue::clone(&value);
+        if !matches!(value.logical_type(), LogicalType::Varchar(_, _)) {
+            value = DataValue::clone(&value)
+                .cast(&LogicalType::Varchar(None, CharLengthUnits::Characters))?;
+        }
+        if let DataValue::Utf8 {
+            value: Some(value),
+            ty,
+            unit,
+        } = &mut value
+        {
+            *value = value.to_lowercase();
+        }
+        Ok(value)
+    }
+
+    fn monotonicity(&self) -> Option<FuncMonotonicity> {
+        todo!()
+    }
+
+    fn return_type(&self) -> &LogicalType {
+        &LogicalType::Varchar(None, CharLengthUnits::Characters)
+    }
+
+    fn summary(&self) -> &FunctionSummary {
+        &self.summary
+    }
+}

src/function/mod.rs

@@ -1,2 +1,4 @@
 pub(crate) mod current_date;
+pub(crate) mod lower;
 pub(crate) mod numbers;
+pub(crate) mod upper;

src/function/upper.rs

@@ -0,0 +1,71 @@
+use crate::catalog::ColumnRef;
+use crate::errors::DatabaseError;
+use crate::expression::function::scala::FuncMonotonicity;
+use crate::expression::function::scala::ScalarFunctionImpl;
+use crate::expression::function::FunctionSummary;
+use crate::expression::ScalarExpression;
+use crate::types::tuple::Tuple;
+use crate::types::value::DataValue;
+use crate::types::LogicalType;
+use serde::Deserialize;
+use serde::Serialize;
+use sqlparser::ast::CharLengthUnits;
+use std::sync::Arc;
+
+#[derive(Debug, Serialize, Deserialize)]
+pub(crate) struct Upper {
+    summary: FunctionSummary,
+}
+
+impl Upper {
+    #[allow(unused_mut)]
+    pub(crate) fn new() -> Arc<Self> {
+        let function_name = "upper".to_lowercase();
+        let arg_types = vec![LogicalType::Varchar(None, CharLengthUnits::Characters)];
+        Arc::new(Self {
+            summary: FunctionSummary {
+                name: function_name,
+                arg_types,
+            },
+        })
+    }
+}
+
+#[typetag::serde]
+impl ScalarFunctionImpl for Upper {
+    #[allow(unused_variables, clippy::redundant_closure_call)]
+    fn eval(
+        &self,
+        exprs: &[ScalarExpression],
+        tuples: &Tuple,
+        columns: &[ColumnRef],
+    ) -> Result<DataValue, DatabaseError> {
+        let value = exprs[0].eval(tuples, columns)?;
+        let mut value = DataValue::clone(&value);
+        if !matches!(value.logical_type(), LogicalType::Varchar(_, _)) {
+            value = DataValue::clone(&value)
+                .cast(&LogicalType::Varchar(None, CharLengthUnits::Characters))?;
+        }
+        if let DataValue::Utf8 {
+            value: Some(value),
+            ty,
+            unit,
+        } = &mut value
+        {
+            *value = value.to_uppercase();
+        }
+        Ok(value)
+    }
+
+    fn monotonicity(&self) -> Option<FuncMonotonicity> {
+        todo!()
+    }
+
+    fn return_type(&self) -> &LogicalType {
+        &LogicalType::Varchar(None, CharLengthUnits::Characters)
+    }
+
+    fn summary(&self) -> &FunctionSummary {
+        &self.summary
+    }
+}

tests/slt/sql_2016/E021_08.slt

@@ -1,13 +1,31 @@
 # E021-08: UPPER and LOWER functions
 
-# TODO: LOWER()/UPPER()
+query T
+SELECT LOWER ( 'FOO' )
+----
+foo
 
-# query T
-# SELECT LOWER ( 'foo' )
-# ----
-# 'foo'
+query T
+SELECT LOWER ( 'foo' )
+----
+foo
 
-# query T
-# SELECT UPPER ( 'foo' )
-# ----
-# 'FOO'
+query T
+SELECT UPPER ( 'foo' )
+----
+FOO
+
+query T
+SELECT UPPER ( 'FOO' )
+----
+FOO
+
+query T
+SELECT UPPER ( LOWER ( 'FOO' ) )
+----
+FOO
+
+query T
+SELECT LOWER ( UPPER ( 'foo' ) )
+----
+foo