address comment from Wenchen

Author: xuanyuanking

docs/sql-keywords.md

@@ -19,7 +19,7 @@ license: |
   limitations under the License.
 ---
 
-When `spark.sql.dialect.spark.ansi.enabled` is true, Spark SQL will use the ANSI mode parser.
+When `spark.sql.ansi.enabled` is true, Spark SQL will use the ANSI mode parser.
 In this mode, Spark SQL has two kinds of keywords:
 * Reserved keywords: Keywords that are reserved and can't be used as identifiers for table, view, column, function, alias, etc.
 * Non-reserved keywords: Keywords that have a special meaning only in particular contexts and can be used as identifiers in other contexts. For example, `SELECT 1 WEEK` is an interval literal, but WEEK can be used as identifiers in other places.

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

@@ -286,11 +286,7 @@ class Analyzer(
           case (_, CalendarIntervalType) => Cast(TimeSub(l, r), l.dataType)
           case (TimestampType, _) => SubtractTimestamps(l, r)
           case (_, TimestampType) => SubtractTimestamps(l, r)
-          case (_, DateType) => if (conf.ansiEnabled) {
-            DateDiff(l, r)
-          } else {
-            SubtractDates(l, r)
-          }
+          case (_, DateType) => SubtractDates(l, r)
           case (DateType, _) => DateSub(l, r)
           case _ => s
         }

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/DateExpressionsSuite.scala

@@ -1131,8 +1131,7 @@ class DateExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
     checkEvaluation(SubtractDates(Literal(end), epochDate),
       IntervalUtils.stringToInterval(UTF8String.fromString("interval 49 years 9 months 4 days")))
     checkEvaluation(SubtractDates(epochDate, Literal(end)),
-      IntervalUtils.stringToInterval(UTF8String.fromString(
-        "interval -49 years -9 months -4 days")))
+      IntervalUtils.stringToInterval(UTF8String.fromString("interval -49 years -9 months -4 days")))
     checkEvaluation(
       SubtractDates(
         Literal(LocalDate.of(10000, 1, 1)),

sql/core/src/test/resources/sql-tests/inputs/postgreSQL/boolean.sql

@@ -22,7 +22,6 @@ SELECT false AS `false`;
 
 SELECT boolean('t') AS true;
 
--- [SPARK-27931] Trim the string when cast string type to boolean type
 SELECT boolean('   f           ') AS `false`;
 
 SELECT boolean('true') AS true;
@@ -49,12 +48,10 @@ SELECT boolean('no') AS `false`;
 -- [SPARK-27923] PostgreSQL does not accept 'nay' but Spark SQL accepts it and sets it to NULL
 SELECT boolean('nay') AS error;
 
--- [SPARK-27931] Accept 'on' and 'off' as input for boolean data type
 SELECT boolean('on') AS true;
 
 SELECT boolean('off') AS `false`;
 
--- [SPARK-27931] Accept unique prefixes thereof
 SELECT boolean('of') AS `false`;
 
 -- [SPARK-27923] PostgreSQL does not accept 'o' but Spark SQL accepts it and sets it to NULL
@@ -101,7 +98,6 @@ SELECT boolean('f') <= boolean('t') AS true;
 
 -- explicit casts to/from text
 SELECT boolean(string('TrUe')) AS true, boolean(string('fAlse')) AS `false`;
--- [SPARK-27931] Trim the string when cast to boolean type
 SELECT boolean(string('    true   ')) AS true,
        boolean(string('     FALSE')) AS `false`;
 SELECT string(boolean(true)) AS true, string(boolean(false)) AS `false`;

sql/core/src/test/resources/sql-tests/inputs/postgreSQL/int2.sql

@@ -92,11 +92,9 @@ WHERE f1 > -32767;
 
 SELECT '' AS five, i.f1, i.f1 - int('2') AS x FROM INT2_TBL i;
 
--- PostgreSQL `/` is the same with Spark `div` since SPARK-2659.
-SELECT '' AS five, i.f1, i.f1 div smallint('2') AS x FROM INT2_TBL i;
+SELECT '' AS five, i.f1, i.f1 / smallint('2') AS x FROM INT2_TBL i;
 
--- PostgreSQL `/` is the same with Spark `div` since SPARK-2659.
-SELECT '' AS five, i.f1, i.f1 div int('2') AS x FROM INT2_TBL i;
+SELECT '' AS five, i.f1, i.f1 / int('2') AS x FROM INT2_TBL i;
 
 -- corner cases
 SELECT string(shiftleft(smallint(-1), 15));

sql/core/src/test/resources/sql-tests/inputs/postgreSQL/int4.sql

@@ -138,7 +138,6 @@ SELECT int('1000') < int('999') AS `false`;
 
 SELECT 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 AS ten;
 
--- [SPARK-2659] HiveQL: Division operator should always perform fractional division
 SELECT 2 + 2 / 2 AS three;
 
 SELECT (2 + 2) / 2 AS two;

sql/core/src/test/resources/sql-tests/inputs/postgreSQL/int8.sql

@@ -87,7 +87,6 @@ SELECT 37 - q1 AS minus4 FROM INT8_TBL;
 SELECT '' AS five, 2 * q1 AS `twice int4` FROM INT8_TBL;
 SELECT '' AS five, q1 * 2 AS `twice int4` FROM INT8_TBL;
 
--- [SPARK-2659] HiveQL: Division operator should always perform fractional division
 -- int8 op int4
 SELECT q1 + int(42) AS `8plus4`, q1 - int(42) AS `8minus4`, q1 * int(42) AS `8mul4`, q1 / int(42) AS `8div4` FROM INT8_TBL;
 -- int4 op int8

sql/core/src/test/resources/sql-tests/results/postgreSQL/date.sql.out

@@ -482,93 +482,93 @@ SELECT date '5874898-01-01'
 -- !query 46
 SELECT f1 - date '2000-01-01' AS `Days From 2K` FROM DATE_TBL
 -- !query 46 schema
-struct<Days From 2K:int>
+struct<Days From 2K:interval>
 -- !query 46 output
--1035
--1036
--1037
--1400
--1401
--1402
--1403
--15542
--15607
-13977
-14343
-14710
-91
-92
-93
+-2 years -10 months
+-2 years -10 months -1 days
+-2 years -9 months -30 days
+-3 years -10 months
+-3 years -10 months -1 days
+-3 years -10 months -2 days
+-3 years -9 months -30 days
+-42 years -6 months -18 days
+-42 years -8 months -22 days
+3 months
+3 months 1 days
+3 months 2 days
+38 years 3 months 7 days
+39 years 3 months 8 days
+40 years 3 months 9 days
 
 
 -- !query 47
 SELECT f1 - date 'epoch' AS `Days From Epoch` FROM DATE_TBL
 -- !query 47 schema
-struct<Days From Epoch:int>
+struct<Days From Epoch:interval>
 -- !query 47 output
--4585
--4650
-11048
-11049
-11050
-24934
-25300
-25667
-9554
-9555
-9556
-9557
-9920
-9921
-9922
+-12 years -6 months -18 days
+-12 years -8 months -22 days
+26 years 1 months 27 days
+26 years 1 months 28 days
+26 years 2 months
+26 years 2 months 1 days
+27 years 1 months 27 days
+27 years 2 months
+27 years 2 months 1 days
+30 years 3 months
+30 years 3 months 1 days
+30 years 3 months 2 days
+68 years 3 months 7 days
+69 years 3 months 8 days
+70 years 3 months 9 days
 
 
 -- !query 48
 SELECT date 'yesterday' - date 'today' AS `One day`
 -- !query 48 schema
-struct<One day:int>
+struct<One day:interval>
 -- !query 48 output
--1
+-1 days
 
 
 -- !query 49
 SELECT date 'today' - date 'tomorrow' AS `One day`
 -- !query 49 schema
-struct<One day:int>
+struct<One day:interval>
 -- !query 49 output
--1
+-1 days
 
 
 -- !query 50
 SELECT date 'yesterday' - date 'tomorrow' AS `Two days`
 -- !query 50 schema
-struct<Two days:int>
+struct<Two days:interval>
 -- !query 50 output
--2
+-2 days
 
 
 -- !query 51
 SELECT date 'tomorrow' - date 'today' AS `One day`
 -- !query 51 schema
-struct<One day:int>
+struct<One day:interval>
 -- !query 51 output
-1
+1 days
 
 
 -- !query 52
 SELECT date 'today' - date 'yesterday' AS `One day`
 -- !query 52 schema
-struct<One day:int>
+struct<One day:interval>
 -- !query 52 output
-1
+1 days
 
 
 -- !query 53
 SELECT date 'tomorrow' - date 'yesterday' AS `Two days`
 -- !query 53 schema
-struct<Two days:int>
+struct<Two days:interval>
 -- !query 53 output
-2
+2 days
 
 
 -- !query 54

sql/core/src/test/resources/sql-tests/results/postgreSQL/int2.sql.out

@@ -266,27 +266,27 @@ struct<five:string,f1:smallint,x:int>
 
 
 -- !query 27
-SELECT '' AS five, i.f1, i.f1 div smallint('2') AS x FROM INT2_TBL i
+SELECT '' AS five, i.f1, i.f1 / smallint('2') AS x FROM INT2_TBL i
 -- !query 27 schema
-struct<five:string,f1:smallint,x:smallint>
+struct<five:string,f1:smallint,x:double>
 -- !query 27 output
-	-1234	-617
-	-32767	-16383
-	0	0
-	1234	617
-	32767	16383
+	-1234	-617.0
+	-32767	-16383.5
+	0	0.0
+	1234	617.0
+	32767	16383.5
 
 
 -- !query 28
-SELECT '' AS five, i.f1, i.f1 div int('2') AS x FROM INT2_TBL i
+SELECT '' AS five, i.f1, i.f1 / int('2') AS x FROM INT2_TBL i
 -- !query 28 schema
-struct<five:string,f1:smallint,x:int>
+struct<five:string,f1:smallint,x:double>
 -- !query 28 output
-	-1234	-617
-	-32767	-16383
-	0	0
-	1234	617
-	32767	16383
+	-1234	-617.0
+	-32767	-16383.5
+	0	0.0
+	1234	617.0
+	32767	16383.5
 
 
 -- !query 29