null - dates

Author: yaooqinn

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala

@@ -863,14 +863,17 @@ object TypeCoercion {
       case Add(l @ NullType(), r @ DateType()) => DateAdd(r, Cast(l, IntegerType))
       case Subtract(l @ DateType(), r @ IntegerType()) => DateSub(l, r)
       case Subtract(l @ DateType(), r @ NullType()) => DateSub(l, Cast(r, IntegerType))
+      case Subtract(l @ NullType(), r @ DateType()) => SubtractDates(Cast(l, DateType), r)
       case Subtract(l @ DateType(), r @ DateType()) =>
         if (SQLConf.get.usePostgreSQLDialect) DateDiff(l, r) else SubtractDates(l, r)
       case Subtract(l @ TimestampType(), r @ TimestampType()) =>
         SubtractTimestamps(l, r)
       case Subtract(l @ TimestampType(), r @ DateType()) =>
         SubtractTimestamps(l, Cast(r, TimestampType))
       case Subtract(l @ TimestampType(), r @ NullType()) =>
-        SubtractTimestamps(l, Cast(r, NullType))
+        SubtractTimestamps(l, Cast(r, TimestampType))
+      case Subtract(l @ NullType(), r @ TimestampType()) =>
+        SubtractTimestamps(Cast(l, TimestampType), r)
       case Subtract(l @ DateType(), r @ TimestampType()) =>
         SubtractTimestamps(Cast(l, TimestampType), r)
     }

sql/core/src/test/resources/sql-tests/inputs/datetime.sql

@@ -43,4 +43,6 @@ select timestamp '2019-01-01\t';
 select date '2001-09-28' + null;
 select date '2001-09-28' - null;
 select null + date '2001-09-28';
-select timestamp'2019-10-06 10:11:12.345678' - null;
+select null - date '2019-10-06';
+select null - timestamp '2019-10-06 10:11:12.345678';
+select timestamp '2019-10-06 10:11:12.345678' - null;

sql/core/src/test/resources/sql-tests/results/datetime.sql.out

@@ -1,5 +1,5 @@
 -- Automatically generated by SQLQueryTestSuite
--- Number of queries: 23
+-- Number of queries: 25
 
 
 -- !query 0
@@ -188,8 +188,24 @@ NULL
 
 
 -- !query 22
-select timestamp'2019-10-06 10:11:12.345678' - null
+select null - date '2019-10-06'
 -- !query 22 schema
-struct<subtracttimestamps(TIMESTAMP '2019-10-06 10:11:12.345678', CAST(CAST(NULL AS NULL) AS TIMESTAMP)):interval>
+struct<subtractdates(CAST(NULL AS DATE), DATE '2019-10-06'):interval>
 -- !query 22 output
 NULL
+
+
+-- !query 23
+select null - timestamp '2019-10-06 10:11:12.345678'
+-- !query 23 schema
+struct<subtracttimestamps(CAST(NULL AS TIMESTAMP), TIMESTAMP '2019-10-06 10:11:12.345678'):interval>
+-- !query 23 output
+NULL
+
+
+-- !query 24
+select timestamp '2019-10-06 10:11:12.345678' - null
+-- !query 24 schema
+struct<subtracttimestamps(TIMESTAMP '2019-10-06 10:11:12.345678', CAST(NULL AS TIMESTAMP)):interval>
+-- !query 24 output
+NULL