feat:implement sql style 'find_in_set' string function

datafusion/expr/src/built_in_function.rs

@@ -304,6 +304,8 @@ pub enum BuiltinScalarFunction {
     Levenshtein,
     /// substr_index
     SubstrIndex,
+    /// find_in_set
+    FindInSet,
 }
 
 /// Maps the sql function name to `BuiltinScalarFunction`
@@ -472,6 +474,7 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::OverLay => Volatility::Immutable,
             BuiltinScalarFunction::Levenshtein => Volatility::Immutable,
             BuiltinScalarFunction::SubstrIndex => Volatility::Immutable,
+            BuiltinScalarFunction::FindInSet => Volatility::Immutable,
 
             // Stable builtin functions
             BuiltinScalarFunction::Now => Volatility::Stable,
@@ -778,6 +781,9 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::SubstrIndex => {
                 utf8_to_str_type(&input_expr_types[0], "substr_index")
             }
+            BuiltinScalarFunction::FindInSet => {
+                utf8_to_int_type(&input_expr_types[0], "find_in_set")
+            }
             BuiltinScalarFunction::ToTimestamp
             | BuiltinScalarFunction::ToTimestampNanos => Ok(Timestamp(Nanosecond, None)),
             BuiltinScalarFunction::ToTimestampMillis => Ok(Timestamp(Millisecond, None)),
@@ -1244,6 +1250,10 @@ impl BuiltinScalarFunction {
                 ],
                 self.volatility(),
             ),
+            BuiltinScalarFunction::FindInSet => Signature::one_of(
+                vec![Exact(vec![Utf8, Utf8]), Exact(vec![LargeUtf8, LargeUtf8])],
+                self.volatility(),
+            ),
 
             BuiltinScalarFunction::Replace | BuiltinScalarFunction::Translate => {
                 Signature::one_of(vec![Exact(vec![Utf8, Utf8, Utf8])], self.volatility())
@@ -1499,6 +1509,7 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::Uuid => &["uuid"],
             BuiltinScalarFunction::Levenshtein => &["levenshtein"],
             BuiltinScalarFunction::SubstrIndex => &["substr_index", "substring_index"],
+            BuiltinScalarFunction::FindInSet => &["find_in_set"],
 
             // regex functions
             BuiltinScalarFunction::RegexpMatch => &["regexp_match"],

datafusion/expr/src/expr_fn.rs

@@ -917,6 +917,7 @@ scalar_expr!(
 scalar_expr!(ArrowTypeof, arrow_typeof, val, "data type");
 scalar_expr!(Levenshtein, levenshtein, string1 string2, "Returns the Levenshtein distance between the two given strings");
 scalar_expr!(SubstrIndex, substr_index, string delimiter count, "Returns the substring from str before count occurrences of the delimiter");
+scalar_expr!(FindInSet, find_in_set, str strlist, "Returns a value in the range of 1 to N if the string str is in the string list strlist consisting of N substrings");
 
 scalar_expr!(
     Struct,
@@ -1207,6 +1208,7 @@ mod test {
         test_nary_scalar_expr!(OverLay, overlay, string, characters, position);
         test_scalar_expr!(Levenshtein, levenshtein, string1, string2);
         test_scalar_expr!(SubstrIndex, substr_index, string, delimiter, count);
+        test_scalar_expr!(FindInSet, find_in_set, string, stringlist);
     }
 
     #[test]

datafusion/physical-expr/src/functions.rs

@@ -885,6 +885,27 @@ pub fn create_physical_fun(
                 ))),
             })
         }
+        BuiltinScalarFunction::FindInSet => Arc::new(|args| match args[0].data_type() {
+            DataType::Utf8 => {
+                let func = invoke_if_unicode_expressions_feature_flag!(
+                    find_in_set,
+                    Int32Type,
+                    "find_in_set"
+                );
+                make_scalar_function(func)(args)
+            }
+            DataType::LargeUtf8 => {
+                let func = invoke_if_unicode_expressions_feature_flag!(
+                    find_in_set,
+                    Int64Type,
+                    "find_in_set"
+                );
+                make_scalar_function(func)(args)
+            }
+            other => Err(DataFusionError::Internal(format!(
+                "Unsupported data type {other:?} for function find_in_set",
+            ))),
+        }),
     })
 }
 

datafusion/physical-expr/src/unicode_expressions.rs

@@ -520,3 +520,42 @@ pub fn substr_index<T: OffsetSizeTrait>(args: &[ArrayRef]) -> Result<ArrayRef> {
 
     Ok(Arc::new(result) as ArrayRef)
 }
+
+///Returns a value in the range of 1 to N if the string str is in the string list strlist consisting of N substrings
+///A string list is a string composed of substrings separated by , characters.
+pub fn find_in_set<T: ArrowPrimitiveType>(args: &[ArrayRef]) -> Result<ArrayRef>
+where
+    T::Native: OffsetSizeTrait,
+{
+    if args.len() != 2 {
+        return internal_err!(
+            "find_in_set was called with {} arguments. It requires 2.",
+            args.len()
+        );
+    }
+
+    let str_array: &GenericStringArray<T::Native> =
+        as_generic_string_array::<T::Native>(&args[0])?;
+    let str_list_array: &GenericStringArray<T::Native> =
+        as_generic_string_array::<T::Native>(&args[1])?;
+
+    let result = str_array
+        .iter()
+        .zip(str_list_array.iter())
+        .map(|(string, str_list)| match (string, str_list) {
+            (Some(string), Some(str_list)) => {
+                let mut res = 0;
+                let str_set: Vec<&str> = str_list.split(',').collect();
+                for (idx, str) in str_set.iter().enumerate() {
+                    if str == &string {
+                        res = idx + 1;
+                        break;
+                    }
+                }
+                T::Native::from_usize(res)
+            }
+            _ => None,
+        })
+        .collect::<PrimitiveArray<T>>();
+    Ok(Arc::new(result) as ArrayRef)
+}

datafusion/proto/proto/datafusion.proto

@@ -642,6 +642,7 @@ enum ScalarFunction {
   ArrayPopFront = 124;
   Levenshtein = 125;
   SubstrIndex = 126;
+  FindInSet = 127;
 }
 
 message ScalarFunctionNode {

datafusion/proto/src/logical_plan/from_proto.rs

@@ -49,8 +49,8 @@ use datafusion_expr::{
     chr, coalesce, concat_expr, concat_ws_expr, cos, cosh, cot, current_date,
     current_time, date_bin, date_part, date_trunc, decode, degrees, digest, encode, exp,
     expr::{self, InList, Sort, WindowFunction},
-    factorial, flatten, floor, from_unixtime, gcd, gen_range, isnan, iszero, lcm, left,
-    levenshtein, ln, log, log10, log2,
+    factorial, find_in_set, flatten, floor, from_unixtime, gcd, gen_range, isnan, iszero,
+    lcm, left, levenshtein, ln, log, log10, log2,
     logical_plan::{PlanType, StringifiedPlan},
     lower, lpad, ltrim, md5, nanvl, now, nullif, octet_length, overlay, pi, power,
     radians, random, regexp_match, regexp_replace, repeat, replace, reverse, right,
@@ -552,6 +552,7 @@ impl From<&protobuf::ScalarFunction> for BuiltinScalarFunction {
             ScalarFunction::OverLay => Self::OverLay,
             ScalarFunction::Levenshtein => Self::Levenshtein,
             ScalarFunction::SubstrIndex => Self::SubstrIndex,
+            ScalarFunction::FindInSet => Self::FindInSet,
         }
     }
 }
@@ -1722,6 +1723,10 @@ pub fn parse_expr(
                     parse_expr(&args[1], registry)?,
                     parse_expr(&args[2], registry)?,
                 )),
+                ScalarFunction::FindInSet => Ok(find_in_set(
+                    parse_expr(&args[0], registry)?,
+                    parse_expr(&args[1], registry)?,
+                )),
                 ScalarFunction::StructFun => {
                     Ok(struct_fun(parse_expr(&args[0], registry)?))
                 }

datafusion/proto/src/logical_plan/to_proto.rs

@@ -1584,6 +1584,7 @@ impl TryFrom<&BuiltinScalarFunction> for protobuf::ScalarFunction {
             BuiltinScalarFunction::OverLay => Self::OverLay,
             BuiltinScalarFunction::Levenshtein => Self::Levenshtein,
             BuiltinScalarFunction::SubstrIndex => Self::SubstrIndex,
+            BuiltinScalarFunction::FindInSet => Self::FindInSet,
         };
 
         Ok(scalar_function)

datafusion/sqllogictest/test_files/functions.slt

@@ -952,3 +952,46 @@ query ?
 SELECT substr_index(NULL, NULL, NULL)
 ----
 NULL
+
+query I
+SELECT find_in_set('b', 'a,b,c,d')
+----
+2
+
+
+query I
+SELECT find_in_set('a', 'a,b,c,d,a')
+----
+1
+
+query I
+SELECT find_in_set('', 'a,b,c,d,a')
+----
+0
+
+query I
+SELECT find_in_set('a', '')
+----
+0
+
+
+query I
+SELECT find_in_set('', '')
+----
+1
+
+query ?
+SELECT find_in_set(NULL, 'a,b,c,d')
+----
+NULL
+
+query I
+SELECT find_in_set('a', NULL)
+----
+NULL
+
+
+query ?
+SELECT find_in_set(NULL, NULL)
+----
+NULL

docs/source/user-guide/sql/scalar_functions.md

@@ -638,6 +638,7 @@ nullif(expression1, expression2)
 - [overlay](#overlay)
 - [levenshtein](#levenshtein)
 - [substr_index](#substr_index)
+- [find_in_set](#find_in_set)
 
 ### `ascii`
 
@@ -1170,6 +1171,20 @@ substr_index(str, delim, count)
 - **delim**: the string to find in str to split str.
 - **count**: The number of times to search for the delimiter. Can be both a positive or negative number.
 
+### `find_in_set`
+
+Returns a value in the range of 1 to N if the string str is in the string list strlist consisting of N substrings.
+For example, `find_in_set('b', 'a,b,c,d') = 2`
+
+```
+find_in_set(str, strlist)
+```
+
+#### Arguments
+
+- **str**: String expression to find in strlist.
+- **strlist**: A string list is a string composed of substrings separated by , characters.
+
 ## Binary String Functions
 
 - [decode](#decode)