[CALCITE-5826] Add FIND_IN_SET function (enabled in Hive and Spark li…

…braries)

core/src/main/java/org/apache/calcite/adapter/enumerable/RexImpTable.java

@@ -178,6 +178,7 @@
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.EXTRACT_VALUE;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.EXTRACT_XML;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.FACTORIAL;
+import static org.apache.calcite.sql.fun.SqlLibraryOperators.FIND_IN_SET;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.FLOOR_BIG_QUERY;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.FORMAT_DATE;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.FORMAT_DATETIME;
@@ -598,6 +599,7 @@ Builder populate() {
       defineReflective(REGEXP_INSTR, BuiltInMethod.REGEXP_INSTR2.method,
           BuiltInMethod.REGEXP_INSTR3.method, BuiltInMethod.REGEXP_INSTR4.method,
           BuiltInMethod.REGEXP_INSTR5.method);
+      defineMethod(FIND_IN_SET, BuiltInMethod.FIND_IN_SET.method, NullPolicy.ANY);
 
       map.put(TRIM, new TrimImplementor());
 

core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java

@@ -146,6 +146,8 @@
 @SuppressWarnings("UnnecessaryUnboxing")
 @Deterministic
 public class SqlFunctions {
+  private static final String COMMA_DELIMITER = ",";
+
   @SuppressWarnings("unused")
   private static final DecimalFormat DOUBLE_FORMAT =
       NumberUtil.decimalFormat("0.0E0");
@@ -1142,6 +1144,29 @@ public static int levenshtein(String string1, String string2) {
     return LEVENSHTEIN_DISTANCE.apply(string1, string2);
   }
 
+  /** SQL FIND_IN_SET(matchStr, textStr) function.
+   * Returns the index (1-based) of the given matchStr
+   * in the comma-delimited list textStr. Returns 0,
+   * if the matchStr is not found or if the matchStr
+   * contains a comma. */
+  public static @Nullable Integer findInSet(
+      @Nullable String matchStr,
+      @Nullable String textStr) {
+    if (matchStr == null || textStr == null) {
+      return null;
+    }
+    if (matchStr.contains(COMMA_DELIMITER)) {
+      return 0;
+    }
+    String[] splits = textStr.split(COMMA_DELIMITER);
+    for (int i = 0; i < splits.length; i++) {
+      if (matchStr.equals(splits[i])) {
+        return i + 1;
+      }
+    }
+    return 0;
+  }
+
   /** SQL ASCII(string) function. */
   public static int ascii(String s) {
     return s.isEmpty()

core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java

@@ -413,6 +413,14 @@ static RelDataType deriveTypeSplit(SqlOperatorBinding operatorBinding,
               OperandTypes.STRING_STRING_OPTIONAL_STRING,
               SqlFunctionCategory.STRING);
 
+  /** The "FIND_IN_SET(matchStr, textStr)" function. */
+  @LibraryOperator(libraries = {HIVE, SPARK})
+  public static final SqlFunction FIND_IN_SET =
+      SqlBasicFunction.create("FIND_IN_SET",
+          ReturnTypes.INTEGER_NULLABLE,
+          OperandTypes.STRING_STRING,
+          SqlFunctionCategory.STRING);
+
   /** The "GREATEST(value, value)" function. */
   @LibraryOperator(libraries = {BIG_QUERY, ORACLE})
   public static final SqlFunction GREATEST =

core/src/main/java/org/apache/calcite/util/BuiltInMethod.java

@@ -379,6 +379,7 @@ public enum BuiltInMethod {
   DIFFERENCE(SqlFunctions.class, "difference", String.class, String.class),
   REVERSE(SqlFunctions.class, "reverse", String.class),
   LEVENSHTEIN(SqlFunctions.class, "levenshtein", String.class, String.class),
+  FIND_IN_SET(SqlFunctions.class, "findInSet", String.class, String.class),
   LEFT(SqlFunctions.class, "left", String.class, int.class),
   RIGHT(SqlFunctions.class, "right", String.class, int.class),
   TO_BASE64(SqlFunctions.class, "toBase64", String.class),

site/_docs/reference.md

@@ -2731,6 +2731,7 @@ BigQuery's type system uses confusingly different names for types and functions:
 | o | EXISTSNODE(xml, xpath, [, namespaces ])        | Determines whether traversal of a XML document using a specified xpath results in any nodes. Returns 0 if no nodes remain after applying the XPath traversal on the document fragment of the element or elements matched by the XPath expression. Returns 1 if any nodes remain. The optional namespace value that specifies a default mapping or namespace mapping for prefixes, which is used when evaluating the XPath expression.
 | m | EXTRACTVALUE(xml, xpathExpr))                  | Returns the text of the first text node which is a child of the element or elements matched by the XPath expression.
 | h s | FACTORIAL(integer)                           | Returns the factorial of *integer*, the range of *integer* is [0, 20]. Otherwise, returns NULL
+| h s | FIND_IN_SET(matchStr, textStr)               | Returns the index (1-based) of the given *matchStr* in the comma-delimited *textStr*. Returns 0, if the given *matchStr* is not found or if the *matchStr* contains a comma. For example, FIND_IN_SET('bc', 'a,bc,def') returns 2
 | b | FLOOR(value)                                   | Similar to standard `FLOOR(value)` except if *value* is an integer type, the return type is a double
 | b | FORMAT_DATE(string, date)                      | Formats *date* according to the specified format *string*
 | b | FORMAT_DATETIME(string, timestamp)             | Formats *timestamp* according to the specified format *string*

testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java

@@ -4701,6 +4701,31 @@ void testBitGetFunc(SqlOperatorFixture f, String functionName) {
     f0.forEachLibrary(list(SqlLibrary.HIVE, SqlLibrary.SPARK), consumer);
   }
 
+  @Test void testFindInSetFunc() {
+    final SqlOperatorFixture f0 = fixture().setFor(SqlLibraryOperators.FIND_IN_SET);
+    f0.checkFails("^find_in_set('ab', 'abc,b,ab,c,def')^",
+        "No match found for function signature FIND_IN_SET\\(<CHARACTER>, <CHARACTER>\\)",
+        false);
+    final Consumer<SqlOperatorFixture> consumer = f -> {
+      f.checkString("find_in_set('ab', 'abc,b,ab,c,def')",
+          "3", "INTEGER NOT NULL");
+      f.checkString("find_in_set('ab', ',,,ab,abc,b,ab,c,def')",
+          "4", "INTEGER NOT NULL");
+      f.checkString("find_in_set('def', ',,,ab,abc,c,def')",
+          "7", "INTEGER NOT NULL");
+      f.checkString("find_in_set(_UTF8'\u4F60\u597D', _UTF8'b,ab,c,def,\u4F60\u597D')",
+          "5", "INTEGER NOT NULL");
+      f.checkString("find_in_set('acd', ',,,ab,abc,c,def')",
+          "0", "INTEGER NOT NULL");
+      f.checkString("find_in_set('ab,', 'abc,b,ab,c,def')",
+          "0", "INTEGER NOT NULL");
+      f.checkNull("find_in_set(cast(null as varchar), 'abc,b,ab,c,def')");
+      f.checkNull("find_in_set('ab', cast(null as varchar))");
+      f.checkNull("find_in_set(cast(null as varchar), cast(null as varchar))");
+    };
+    f0.forEachLibrary(list(SqlLibrary.HIVE, SqlLibrary.SPARK), consumer);
+  }
+
   @Test void testIfFunc() {
     final SqlOperatorFixture f = fixture();
     checkIf(f.withLibrary(SqlLibrary.BIG_QUERY));