Merge pull request #54316 from ucasfl/isNull

Fix isZeroOrNull(NULL)

docs/en/sql-reference/functions/functions-for-nulls.md

@@ -92,6 +92,50 @@ Result:
 └───┘
 ```
 
+## isZeroOrNull
+
+Returns whether the argument is 0 (zero) or [NULL](../../sql-reference/syntax.md#null-literal).
+
+``` sql
+isZeroOrNull(x)
+```
+
+**Arguments:**
+
+- `x` — A value of non-compound data type.
+
+**Returned value**
+
+- `1` if `x` is 0 (zero) or `NULL`.
+- `0` else.
+
+**Example**
+
+Table:
+
+``` text
+┌─x─┬────y─┐
+│ 1 │ ᴺᵁᴸᴸ │
+│ 2 │    0 │
+│ 3 │    3 │
+└───┴──────┘
+```
+
+Query:
+
+``` sql
+SELECT x FROM t_null WHERE isZeroOrNull(y);
+```
+
+Result:
+
+``` text
+┌─x─┐
+│ 1 │
+│ 2 │
+└───┘
+```
+
 ## coalesce
 
 Returns the leftmost non-`NULL` argument.

src/Functions/isZeroOrNull.cpp

@@ -44,14 +44,18 @@ public:
 
     DataTypePtr getReturnTypeImpl(const DataTypes & types) const override
     {
-        if (!isNumber(removeNullable(types.at(0))))
-            throw Exception(ErrorCodes::BAD_ARGUMENTS, "The argument of function {} must have simple numeric type, possibly Nullable", name);
+        if (!isNumber(removeNullable(types.at(0))) && !isNothing(removeNullable(types.at(0))))
+            throw Exception(
+                ErrorCodes::BAD_ARGUMENTS, "The argument of function {} must have simple numeric type, possibly Nullable or Null", name);
 
         return std::make_shared<DataTypeUInt8>();
     }
 
     ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
     {
+        if (isNothing(removeNullable(arguments[0].type)))
+            return DataTypeUInt8{}.createColumnConst(input_rows_count, 1);
+
         const ColumnPtr & input_column = arguments[0].column;
 
         ColumnPtr res;
@@ -72,7 +76,10 @@ public:
                     return true;
                 }))
             {
-                throw Exception(ErrorCodes::ILLEGAL_COLUMN, "The argument of function {} must have simple numeric type, possibly Nullable", name);
+                throw Exception(
+                    ErrorCodes::ILLEGAL_COLUMN,
+                    "The argument of function {} must have simple numeric type, possibly Nullable or Null",
+                    name);
             }
         }
         else
@@ -89,7 +96,10 @@ public:
                     return true;
                 }))
             {
-                throw Exception(ErrorCodes::ILLEGAL_COLUMN, "The argument of function {} must have simple numeric type, possibly Nullable", name);
+                throw Exception(
+                    ErrorCodes::ILLEGAL_COLUMN,
+                    "The argument of function {} must have simple numeric type, possibly Nullable or Null",
+                    name);
             }
         }
 

tests/queries/0_stateless/01373_is_zero_or_null.reference

@@ -20,3 +20,5 @@ world
 3
 ---
 4
+---
+1

tests/queries/0_stateless/01373_is_zero_or_null.sql

@@ -27,3 +27,7 @@ SELECT count() FROM
     UNION ALL
     SELECT * FROM test WHERE isZeroOrNull(x != 'xyz')
 );
+
+SELECT '---';
+
+select isZeroOrNull(Null);

utils/check-style/aspell-ignore/en/aspell-dict.txt

@@ -1329,10 +1329,10 @@ ddl
 deallocation
 deallocations
 debian
+decodeHTMLComponent
 decodeURLComponent
 decodeURLFormComponent
 decodeXMLComponent
-decodeHTMLComponent
 decompressor
 decrypt
 decrypted
@@ -1558,6 +1558,7 @@ gzipped
 hadoop
 halfMD
 halfday
+hardlink
 hardlinks
 hasAll
 hasAny
@@ -1637,6 +1638,7 @@ isNotNull
 isNull
 isValidJSON
 isValidUTF
+isZeroOrNull
 iteratively
 jaccard
 javaHash
@@ -2582,4 +2584,3 @@ znode
 znodes
 zookeeperSessionUptime
 zstd
-hardlink