Calcite 1.30 implement CHAR function

gleonSun · Feb 13, 2023 · 0e1f6b0 · 0e1f6b0
1 parent 6dd5345
commit 0e1f6b0
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diff --git a/core/src/main/codegen/templates/Parser.jj b/core/src/main/codegen/templates/Parser.jj
@@ -6919,6 +6919,7 @@ SqlIdentifier ReservedFunctionName() :
     |   <AVG>
     |   <CARDINALITY>
     |   <CEILING>
+    |   <CHAR>
     |   <CHAR_LENGTH>
     |   <CHARACTER_LENGTH>
     |   <COALESCE>

diff --git a/core/src/main/java/org/apache/calcite/adapter/enumerable/RexImpTable.java b/core/src/main/java/org/apache/calcite/adapter/enumerable/RexImpTable.java
@@ -116,6 +116,7 @@
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.ARRAY_REVERSE;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.BOOL_AND;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.BOOL_OR;
+import static org.apache.calcite.sql.fun.SqlLibraryOperators.CHAR;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.CHR;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.COMPRESS;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.CONCAT2;
@@ -368,6 +369,8 @@ public class RexImpTable {
     defineMethod(REPLACE, BuiltInMethod.REPLACE.method, NullPolicy.STRICT);
     defineMethod(TRANSLATE3, BuiltInMethod.TRANSLATE3.method, NullPolicy.STRICT);
     defineMethod(CHR, "chr", NullPolicy.STRICT);
+    // Calcite 1.30 removed SqlFunction CHAR, support this function
+    defineMethod(CHAR, BuiltInMethod.CHAR.method, NullPolicy.STRICT);
     defineMethod(CHARACTER_LENGTH, BuiltInMethod.CHAR_LENGTH.method,
         NullPolicy.STRICT);
     defineMethod(CHAR_LENGTH, BuiltInMethod.CHAR_LENGTH.method,

diff --git a/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java b/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java
@@ -523,6 +523,14 @@ public static int octetLength(ByteString s) {
     return s.length();
   }
 
+  /** Calcite 1.30 removed SqlFunction CHAR, support this function */
+  public static String charN(long n) {
+    if (n < 0) {
+      return null;
+    }
+    return String.valueOf(Character.toChars((int) (n % 256)));
+  }
+
   /** SQL CHARACTER_LENGTH(string) function. */
   public static int charLength(String s) {
     if (s == null) {

diff --git a/core/src/main/java/org/apache/calcite/sql/SqlJdbcFunctionCall.java b/core/src/main/java/org/apache/calcite/sql/SqlJdbcFunctionCall.java
@@ -689,6 +689,8 @@ private JdbcToInternalLookupTable() {
       map.put("ATAN2", simple(SqlStdOperatorTable.ATAN2));
       map.put("CBRT", simple(SqlStdOperatorTable.CBRT));
       map.put("CEILING", simple(SqlStdOperatorTable.CEIL));
+      // Calcite 1.30 removed SqlFunction CHAR, support this function
+      map.put("CHAR", simple(SqlLibraryOperators.CHAR));
       map.put("COS", simple(SqlStdOperatorTable.COS));
       map.put("COT", simple(SqlStdOperatorTable.COT));
       map.put("DEGREES", simple(SqlStdOperatorTable.DEGREES));

diff --git a/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java b/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java
@@ -659,6 +659,16 @@ private SqlLibraryOperators() {
           OperandTypes.INTEGER,
           SqlFunctionCategory.STRING);
 
+  // Calcite 1.30 removed SqlFunction CHAR, support this function
+  @LibraryOperator(libraries = {MYSQL, SPARK})
+  public static final SqlFunction CHAR =
+      new SqlFunction("CHAR",
+          SqlKind.OTHER_FUNCTION,
+          ReturnTypes.CHAR_FORCE_NULLABLE,
+          null,
+          OperandTypes.INTEGER,
+          SqlFunctionCategory.STRING);
+
   @LibraryOperator(libraries = {ORACLE})
   public static final SqlFunction TANH =
       new SqlFunction("TANH",

diff --git a/core/src/main/java/org/apache/calcite/sql/type/ReturnTypes.java b/core/src/main/java/org/apache/calcite/sql/type/ReturnTypes.java
@@ -367,6 +367,14 @@ public RelDataType inferReturnType(
   public static final SqlReturnTypeInference CHAR =
           explicit(SqlTypeName.CHAR);
 
+  /**
+   * Calcite 1.30 removed SqlFunction CHAR, support this function
+   * Type-inference strategy whereby the result type of a call is a nullable
+   * CHAR(1).
+   */
+  public static final SqlReturnTypeInference CHAR_FORCE_NULLABLE =
+      ReturnTypes.cascade(ReturnTypes.CHAR, SqlTypeTransforms.FORCE_NULLABLE);
+
   /**
    * Type-inference strategy whereby the result type of a call is an Integer.
    */

diff --git a/core/src/main/java/org/apache/calcite/util/BuiltInMethod.java b/core/src/main/java/org/apache/calcite/util/BuiltInMethod.java
@@ -396,6 +396,8 @@ public enum BuiltInMethod {
   SUBSTRING(SqlFunctions.class, "substring", String.class, int.class,
       int.class),
   OCTET_LENGTH(SqlFunctions.class, "octetLength", ByteString.class),
+  // Calcite 1.30 removed SqlFunction CHAR, support this function
+  CHAR(SqlFunctions.class, "charN", long.class),
   CHAR_LENGTH(SqlFunctions.class, "charLength", String.class),
   STRING_CONCAT(SqlFunctions.class, "concat", String.class, String.class),
   MULTI_STRING_CONCAT(SqlFunctions.class, "concatMulti", String[].class),

diff --git a/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java b/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
@@ -1620,6 +1620,25 @@ protected static Calendar getCalendarNotTooNear(int timeUnit) {
 
   }
 
+  // Calcite 1.30 removed SqlFunction CHAR, support this function
+  @Test void testChar() {
+    final SqlOperatorFixture f0 = fixture()
+        .setFor(SqlLibraryOperators.CHAR, VM_FENNEL, VM_JAVA);
+    f0.checkFails("^char(97)^",
+        "No match found for function signature CHAR\\(<NUMERIC>\\)", false);
+    final SqlOperatorFixture f = f0.withLibrary(SqlLibrary.MYSQL);
+    f.checkScalar("char(null)", isNullValue(), "CHAR(1)");
+    f.checkScalar("char(-1)", isNullValue(), "CHAR(1)");
+    f.checkScalar("char(97)", "a", "CHAR(1)");
+    f.checkScalar("char(48)", "0", "CHAR(1)");
+    f.checkScalar("char(0)", String.valueOf('\u0000'), "CHAR(1)");
+    f.checkFails("^char(97.1)^",
+        "Cannot apply 'CHAR' to arguments of type 'CHAR\\(<DECIMAL\\(3, 1\\)>\\)'\\. "
+            + "Supported form\\(s\\): 'CHAR\\(<INTEGER>\\)'",
+        false);
+    f.checkScalarExact("char('abc')", "CHAR(1)", "CHAR");
+  }
+
   @Test void testChr() {
     final SqlOperatorFixture f0 = fixture()
         .setFor(SqlLibraryOperators.CHR, VM_FENNEL, VM_JAVA);