diff --git a/datafusion/expr/src/type_coercion/functions.rs b/datafusion/expr/src/type_coercion/functions.rs
index 6836713d8016..c81d59267c7f 100644
--- a/datafusion/expr/src/type_coercion/functions.rs
+++ b/datafusion/expr/src/type_coercion/functions.rs
@@ -424,15 +424,25 @@ fn get_valid_types(
             let mut new_types = Vec::with_capacity(current_types.len());
             for data_type in current_types.iter() {
                 let logical_data_type: NativeType = data_type.into();
-                if logical_data_type == NativeType::String {
-                    new_types.push(data_type.to_owned());
-                } else if logical_data_type == NativeType::Null {
-                    // TODO: Switch to Utf8View if all the string functions supports Utf8View
-                    new_types.push(DataType::Utf8);
-                } else {
-                    return plan_err!(
-                        "The signature expected NativeType::String but received {logical_data_type}"
-                    );
+                match logical_data_type {
+                    NativeType::String => {
+                        new_types.push(data_type.to_owned());
+                    }
+                    // Allow implicit casting
+                    NativeType::Null
+                    | NativeType::Int32
+                    | NativeType::Int64
+                    | NativeType::Float32
+                    | NativeType::Float64
+                    | NativeType::Boolean => {
+                        // TODO: Switch to Utf8View if all the string functions supports Utf8View
+                        new_types.push(DataType::Utf8);
+                    }
+                    _ => {
+                        return plan_err!(
+                            "The signature expected NativeType::String but received {logical_data_type}"
+                        );
+                    }
                 }
             }
 
diff --git a/datafusion/sqllogictest/test_files/expr.slt b/datafusion/sqllogictest/test_files/expr.slt
index c653113fd438..b2df1cdb40ba 100644
--- a/datafusion/sqllogictest/test_files/expr.slt
+++ b/datafusion/sqllogictest/test_files/expr.slt
@@ -510,6 +510,42 @@ SELECT ltrim(NULL, 'xyz')
 ----
 NULL
 
+# implicit casting with TypeSignature test
+query T
+SELECT ltrim(NULL, NULL)
+----
+NULL
+
+query T
+SELECT ltrim(12345, '1')
+----
+2345
+
+query T
+SELECT ltrim(10020, '0')
+----
+10020
+
+query T
+SELECT ltrim(12.345, '12')
+----
+.345
+
+query T
+SELECT ltrim(0.00123, '0.')
+----
+123
+
+query T
+SELECT ltrim(true, 't')
+----
+rue
+
+query T
+SELECT ltrim(false, 'f')
+----
+alse
+
 query I
 SELECT octet_length('')
 ----
diff --git a/datafusion/sqllogictest/test_files/scalar.slt b/datafusion/sqllogictest/test_files/scalar.slt
index fe7d1a90c5bd..1ab5444db1a3 100644
--- a/datafusion/sqllogictest/test_files/scalar.slt
+++ b/datafusion/sqllogictest/test_files/scalar.slt
@@ -1940,9 +1940,6 @@ select position('' in '')
 ----
 1
 
-query error DataFusion error: Error during planning: Error during planning: The signature expected NativeType::String but received NativeType::Int64
-select position(1 in 1)
-
 query I
 select strpos('abc', 'c');
 ----