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

…brary)

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

@@ -174,6 +174,7 @@
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.EXISTS_NODE;
 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.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;
@@ -586,6 +587,7 @@ 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.STRICT);
 
       map.put(TRIM, new TrimImplementor());
 

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

@@ -1076,6 +1076,32 @@ public static int levenshtein(String string1, String string2) {
     return LEVENSHTEIN_DISTANCE.apply(string1, string2);
   }
 
+  /** SQL FIND_IN_SET(string, stringArray)" function. */
+  public static int findInSet(String matchStr, String textStr) {
+    if (matchStr.contains(",")) {
+      return 0;
+    }
+    int textStrLen = textStr.length();
+    int matchStrLen = matchStr.length();
+    int n = 1;
+    int lastComma = -1;
+    for (int i = 0; i < textStrLen; i++) {
+      if (textStr.charAt(i) == ',') {
+        if (i - (lastComma + 1) == matchStrLen
+            && textStr.substring(lastComma + 1, i).equals(matchStr)) {
+          return n;
+        }
+        lastComma = i;
+        n++;
+      }
+    }
+    if (textStrLen - (lastComma + 1) == matchStrLen
+        && textStr.substring(lastComma + 1, textStrLen).equals(matchStr)) {
+      return n;
+    }
+    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

@@ -405,6 +405,14 @@ static RelDataType deriveTypeSplit(SqlOperatorBinding operatorBinding,
               OperandTypes.STRING_STRING_OPTIONAL_STRING,
               SqlFunctionCategory.STRING);
 
+  /** The "FIND_IN_SET(string, stringArray)" 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

@@ -371,6 +371,7 @@ 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

@@ -2736,6 +2736,7 @@ BigQuery's type system uses confusingly different names for types and functions:
 | h s | FORMAT_NUMBER(value, format)                 | Formats the number *value* to MySQL's FORMAT *format*, like '#,###,###.##0.00'
 | b | FORMAT_TIME(string, time)                      | Formats *time* according to the specified format *string*
 | b | FORMAT_TIMESTAMP(string timestamp)             | Formats *timestamp* according to the specified format *string*
+| h s | FIND_IN_SET(string, stringArray)             | Returns the index (1-based) of the given *string* in the comma-delimited *stringArray*  Returns 0, if the given *string* was not found or if *string* contains a comma
 | s | GETBIT(value, position)                        | Equivalent to `BIT_GET(value, position)`
 | b o | GREATEST(expr [, expr ]*)                    | Returns the greatest of the expressions
 | b h s | IF(condition, value1, value2)              | Returns *value1* if *condition* is TRUE, *value2* otherwise

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

@@ -4573,6 +4573,31 @@ 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));