[BUG]: sql functions case sensitivit (#3063)

closes #3056

src/daft-sql/src/functions.rs

@@ -230,7 +230,8 @@ impl SQLPlanner {
 
         // lookup function variant(s) by name
         let fns = &SQL_FUNCTIONS;
-        let fn_name = func.name.to_string();
+        // SQL function names are case-insensitive
+        let fn_name = func.name.to_string().to_lowercase();
         let fn_match = match fns.get(&fn_name) {
             Some(func) => func,
             None => unsupported_sql_err!("Function `{}` not found", fn_name),

src/daft-sql/src/lib.rs

@@ -314,6 +314,10 @@ mod tests {
     #[case::ilike("select utf8 ilike 'a' as ilike from tbl1")]
     #[case::datestring("select DATE '2021-08-01' as dt from tbl1")]
     #[case::datetime("select DATETIME '2021-08-01 00:00:00' as dt from tbl1")]
+    #[case::countstar("select COUNT(*) as count from tbl1")]
+    #[case::countstarlower("select COUNT(*) as count from tbl1")]
+    #[case::count("select COUNT(i32) as count from tbl1")]
+    #[case::countcasing("select CoUnT(i32) as count from tbl1")]
     // #[case::to_datetime("select to_datetime(utf8, 'YYYY-MM-DD') as to_datetime from tbl1")]
     fn test_compiles_funcs(mut planner: SQLPlanner, #[case] query: &str) -> SQLPlannerResult<()> {
         let plan = planner.plan_sql(query);

tests/sql/test_exprs.py

@@ -69,6 +69,18 @@ def test_hash_exprs():
         daft.sql("SELECT minhash(a) as hash_a FROM df").collect()
 
 
+def test_count_star():
+    df = daft.from_pydict(
+        {
+            "a": [1, 2, 3, 4],
+        }
+    )
+
+    actual = daft.sql("SELECT COUNT(*) FROM df").collect()
+    expected = df.agg(daft.col("*").count().alias("count")).collect()
+    assert actual.to_pydict() == expected.to_pydict()
+
+
 def test_between():
     df = daft.from_pydict(
         {