use {
super::ExprNode,
crate::{
ast::{Aggregate, CountArgExpr},
parse_sql::parse_expr,
result::{Error, Result},
translate::translate_expr,
},
};
#[derive(Clone, Debug)]
pub enum AggregateNode<'a> {
Count(CountArgExprNode<'a>),
Sum(ExprNode<'a>),
Min(ExprNode<'a>),
Max(ExprNode<'a>),
Avg(ExprNode<'a>),
Variance(ExprNode<'a>),
Stdev(ExprNode<'a>),
}
#[derive(Clone, Debug)]
pub enum CountArgExprNode<'a> {
Text(String),
Expr(ExprNode<'a>),
}
impl<'a> From<&'a str> for CountArgExprNode<'a> {
fn from(count_arg_str: &str) -> Self {
Self::Text(count_arg_str.to_owned())
}
}
impl<'a> From<ExprNode<'a>> for CountArgExprNode<'a> {
fn from(expr_node: ExprNode<'a>) -> Self {
Self::Expr(expr_node)
}
}
impl<'a> TryFrom<CountArgExprNode<'a>> for CountArgExpr {
type Error = Error;
fn try_from(count_expr_node: CountArgExprNode<'a>) -> Result<Self> {
match count_expr_node {
CountArgExprNode::Text(s) if &s == "*" => Ok(CountArgExpr::Wildcard),
CountArgExprNode::Text(s) => {
let expr = parse_expr(s).and_then(|expr| translate_expr(&expr))?;
Ok(CountArgExpr::Expr(expr))
}
CountArgExprNode::Expr(expr_node) => expr_node.try_into().map(CountArgExpr::Expr),
}
}
}
impl<'a> TryFrom<AggregateNode<'a>> for Aggregate {
type Error = Error;
fn try_from(aggr_node: AggregateNode<'a>) -> Result<Self> {
match aggr_node {
AggregateNode::Count(count_arg_expr_node) => {
count_arg_expr_node.try_into().map(Aggregate::Count)
}
AggregateNode::Sum(expr_node) => expr_node.try_into().map(Aggregate::Sum),
AggregateNode::Min(expr_node) => expr_node.try_into().map(Aggregate::Min),
AggregateNode::Max(expr_node) => expr_node.try_into().map(Aggregate::Max),
AggregateNode::Avg(expr_node) => expr_node.try_into().map(Aggregate::Avg),
AggregateNode::Variance(expr_node) => expr_node.try_into().map(Aggregate::Variance),
AggregateNode::Stdev(expr_node) => expr_node.try_into().map(Aggregate::Stdev),
}
}
}
impl<'a> ExprNode<'a> {
pub fn count(self) -> Self {
count(self)
}
pub fn sum(self) -> Self {
sum(self)
}
pub fn min(self) -> Self {
min(self)
}
pub fn max(self) -> Self {
max(self)
}
pub fn avg(self) -> Self {
avg(self)
}
pub fn variance(self) -> Self {
variance(self)
}
pub fn stdev(self) -> Self {
stdev(self)
}
}
pub fn count<'a, T: Into<CountArgExprNode<'a>>>(expr: T) -> ExprNode<'a> {
ExprNode::Aggregate(Box::new(AggregateNode::Count(expr.into())))
}
pub fn sum<'a, T: Into<ExprNode<'a>>>(expr: T) -> ExprNode<'a> {
ExprNode::Aggregate(Box::new(AggregateNode::Sum(expr.into())))
}
pub fn min<'a, T: Into<ExprNode<'a>>>(expr: T) -> ExprNode<'a> {
ExprNode::Aggregate(Box::new(AggregateNode::Min(expr.into())))
}
pub fn max<'a, T: Into<ExprNode<'a>>>(expr: T) -> ExprNode<'a> {
ExprNode::Aggregate(Box::new(AggregateNode::Max(expr.into())))
}
pub fn avg<'a, T: Into<ExprNode<'a>>>(expr: T) -> ExprNode<'a> {
ExprNode::Aggregate(Box::new(AggregateNode::Avg(expr.into())))
}
pub fn variance<'a, T: Into<ExprNode<'a>>>(expr: T) -> ExprNode<'a> {
ExprNode::Aggregate(Box::new(AggregateNode::Variance(expr.into())))
}
pub fn stdev<'a, T: Into<ExprNode<'a>>>(expr: T) -> ExprNode<'a> {
ExprNode::Aggregate(Box::new(AggregateNode::Stdev(expr.into())))
}
#[cfg(test)]
mod tests {
use crate::ast_builder::{avg, col, count, max, min, stdev, sum, test_expr, variance};
#[test]
fn aggregate() {
let actual = col("id").count();
let expected = "COUNT(id)";
test_expr(actual, expected);
let actual = count("id");
let expected = "COUNT(id)";
test_expr(actual, expected);
let actual = count("*");
let expected = "COUNT(*)";
test_expr(actual, expected);
let actual = col("amount").sum();
let expected = "SUM(amount)";
test_expr(actual, expected);
let actual = sum("amount");
let expected = "SUM(amount)";
test_expr(actual, expected);
let actual = col("budget").min();
let expected = "MIN(budget)";
test_expr(actual, expected);
let actual = min("budget");
let expected = "MIN(budget)";
test_expr(actual, expected);
let actual = col("score").max();
let expected = "MAX(score)";
test_expr(actual, expected);
let actual = max("score");
let expected = "MAX(score)";
test_expr(actual, expected);
let actual = col("grade").avg();
let expected = "AVG(grade)";
test_expr(actual, expected);
let actual = avg("grade");
let expected = "AVG(grade)";
test_expr(actual, expected);
let actual = col("statistic").variance();
let expected = "VARIANCE(statistic)";
test_expr(actual, expected);
let actual = variance("statistic");
let expected = "VARIANCE(statistic)";
test_expr(actual, expected);
let actual = col("scatterplot").stdev();
let expected = "STDEV(scatterplot)";
test_expr(actual, expected);
let actual = stdev("scatterplot");
let expected = "STDEV(scatterplot)";
test_expr(actual, expected);
}
}