[SPARK-28029][SQL][TEST] Port int2.sql

## What changes were proposed in this pull request?

This PR is to port int2.sql from PostgreSQL regression tests. https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/sql/int2.sql

The expected results can be found in the link: https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/expected/int2.out

When porting the test cases, found two PostgreSQL specific features that do not exist in Spark SQL:
[SPARK-28023](https://issues.apache.org/jira/browse/SPARK-28023): Trim the string when cast string type to other types
[SPARK-28027](https://issues.apache.org/jira/browse/SPARK-28027): Add bitwise shift left/right operators

Also, found a bug:
[SPARK-28024](https://issues.apache.org/jira/browse/SPARK-28024): Incorrect value when out of range

Also, found three inconsistent behavior:
[SPARK-27923](https://issues.apache.org/jira/browse/SPARK-27923): Invalid input syntax for smallint throws exception at PostgreSQL
[SPARK-28028](https://issues.apache.org/jira/browse/SPARK-28028): Cast numeric to integral type need round
[SPARK-2659](https://issues.apache.org/jira/browse/SPARK-2659): HiveQL: Division operator should always perform fractional division, for example:
```sql
select 1/2;
```

## How was this patch tested?

N/A

Closes apache#24853 from wangyum/SPARK-28029.

Authored-by: Yuming Wang <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: wangyum

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

@@ -0,0 +1,129 @@
+--
+-- Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
+--
+--
+-- INT2
+-- https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/sql/int2.sql
+
+CREATE TABLE INT2_TBL(f1 smallint) USING parquet;
+
+-- [SPARK-28023] Trim the string when cast string type to other types
+INSERT INTO INT2_TBL VALUES (trim('0   '));
+
+INSERT INTO INT2_TBL VALUES (trim('  1234 '));
+
+INSERT INTO INT2_TBL VALUES (trim('    -1234'));
+
+-- [SPARK-27923] Invalid input syntax for type short throws exception at PostgreSQL
+-- INSERT INTO INT2_TBL VALUES ('34.5');
+
+-- largest and smallest values
+INSERT INTO INT2_TBL VALUES ('32767');
+
+INSERT INTO INT2_TBL VALUES ('-32767');
+
+-- bad input values -- should give errors
+-- INSERT INTO INT2_TBL VALUES ('100000');
+-- INSERT INTO INT2_TBL VALUES ('asdf');
+-- INSERT INTO INT2_TBL VALUES ('    ');
+-- INSERT INTO INT2_TBL VALUES ('- 1234');
+-- INSERT INTO INT2_TBL VALUES ('4 444');
+-- INSERT INTO INT2_TBL VALUES ('123 dt');
+-- INSERT INTO INT2_TBL VALUES ('');
+
+
+SELECT '' AS five, * FROM INT2_TBL;
+
+SELECT '' AS four, i.* FROM INT2_TBL i WHERE i.f1 <> smallint('0');
+
+SELECT '' AS four, i.* FROM INT2_TBL i WHERE i.f1 <> int('0');
+
+SELECT '' AS one, i.* FROM INT2_TBL i WHERE i.f1 = smallint('0');
+
+SELECT '' AS one, i.* FROM INT2_TBL i WHERE i.f1 = int('0');
+
+SELECT '' AS two, i.* FROM INT2_TBL i WHERE i.f1 < smallint('0');
+
+SELECT '' AS two, i.* FROM INT2_TBL i WHERE i.f1 < int('0');
+
+SELECT '' AS three, i.* FROM INT2_TBL i WHERE i.f1 <= smallint('0');
+
+SELECT '' AS three, i.* FROM INT2_TBL i WHERE i.f1 <= int('0');
+
+SELECT '' AS two, i.* FROM INT2_TBL i WHERE i.f1 > smallint('0');
+
+SELECT '' AS two, i.* FROM INT2_TBL i WHERE i.f1 > int('0');
+
+SELECT '' AS three, i.* FROM INT2_TBL i WHERE i.f1 >= smallint('0');
+
+SELECT '' AS three, i.* FROM INT2_TBL i WHERE i.f1 >= int('0');
+
+-- positive odds
+SELECT '' AS one, i.* FROM INT2_TBL i WHERE (i.f1 % smallint('2')) = smallint('1');
+
+-- any evens
+SELECT '' AS three, i.* FROM INT2_TBL i WHERE (i.f1 % int('2')) = smallint('0');
+
+-- [SPARK-28024] Incorrect value when out of range
+-- SELECT '' AS five, i.f1, i.f1 * smallint('2') AS x FROM INT2_TBL i;
+
+SELECT '' AS five, i.f1, i.f1 * smallint('2') AS x FROM INT2_TBL i
+WHERE abs(f1) < 16384;
+
+SELECT '' AS five, i.f1, i.f1 * int('2') AS x FROM INT2_TBL i;
+
+-- [SPARK-28024] Incorrect value when out of range
+-- SELECT '' AS five, i.f1, i.f1 + smallint('2') AS x FROM INT2_TBL i;
+
+SELECT '' AS five, i.f1, i.f1 + smallint('2') AS x FROM INT2_TBL i
+WHERE f1 < 32766;
+
+SELECT '' AS five, i.f1, i.f1 + int('2') AS x FROM INT2_TBL i;
+
+-- [SPARK-28024] Incorrect value when out of range
+-- SELECT '' AS five, i.f1, i.f1 - smallint('2') AS x FROM INT2_TBL i;
+
+SELECT '' AS five, i.f1, i.f1 - smallint('2') AS x FROM INT2_TBL i
+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;
+
+-- 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;
+
+-- corner cases
+SELECT string(shiftleft(smallint(-1), 15));
+SELECT string(smallint(shiftleft(smallint(-1), 15))+1);
+
+-- check sane handling of INT16_MIN overflow cases
+-- [SPARK-28024] Incorrect numeric values when out of range
+-- SELECT smallint((-32768)) * smallint(-1);
+-- SELECT smallint(-32768) / smallint(-1);
+SELECT smallint(-32768) % smallint(-1);
+
+-- [SPARK-28028] Cast numeric to integral type need round
+-- check rounding when casting from float
+SELECT x, smallint(x) AS int2_value
+FROM (VALUES float(-2.5),
+             float(-1.5),
+             float(-0.5),
+             float(0.0),
+             float(0.5),
+             float(1.5),
+             float(2.5)) t(x);
+
+-- [SPARK-28028] Cast numeric to integral type need round
+-- check rounding when casting from numeric
+SELECT x, smallint(x) AS int2_value
+FROM (VALUES cast(-2.5 as decimal(38, 18)),
+             cast(-1.5 as decimal(38, 18)),
+             cast(-0.5 as decimal(38, 18)),
+             cast(-0.0 as decimal(38, 18)),
+             cast(0.5 as decimal(38, 18)),
+             cast(1.5 as decimal(38, 18)),
+             cast(2.5 as decimal(38, 18))) t(x);
+
+DROP TABLE INT2_TBL;