[PlSql] Add POSITION as keyword & allow as a column name (antlr#4287)

Author: Naros

sql/plsql/PlSqlLexer.g4

@@ -1377,6 +1377,7 @@ POOL_2K                        : 'POOL_2K';
 POOL_32K                       : 'POOL_32K';
 POOL_4K                        : 'POOL_4K';
 POOL_8K                        : 'POOL_8K';
+POSITION                       : 'POSITION';
 POSITIVEN                      : 'POSITIVEN';
 POSITIVE                       : 'POSITIVE';
 POST_TRANSACTION               : 'POST_TRANSACTION';

sql/plsql/PlSqlParser.g4

@@ -8940,6 +8940,7 @@ non_reserved_keywords_pre12c
     | POWERMULTISET_BY_CARDINALITY
     | POWERMULTISET
     | POWER
+    | POSITION
     | PQ_DISTRIBUTE
     | PQ_MAP
     | PQ_NOMAP

sql/plsql/examples/create_table.sql

@@ -449,3 +449,39 @@ CREATE INDEX part_idx ON partitioned_by_index (part, val)
         ( PARTITION t0 VALUES LESS THAN (TIMESTAMP '2020-01-01 00:00:00')
         , PARTITION t1 VALUES LESS THAN (MAXVALUE) )
         ;
+
+CREATE TABLE TBHSP27E (
+ compid VARCHAR2(20) default '' not null,
+ empno VARCHAR2(20) default '' not null,
+ salarymonth VARCHAR2(10) default '' not null,
+ position VARCHAR2(10) default '' not null,
+ posttype VARCHAR2(10) default '',
+ deptno VARCHAR2(10) default '',
+ startdate VARCHAR2(8) default '',
+ enddate VARCHAR2(8) default '',
+ accounttype VARCHAR2(10) default '',
+ attendrate NUMBER(10,4) default 0,
+ meritscore VARCHAR2(10) default '',
+ excitationfactor NUMBER(20,2) default 0,
+ basesalary NUMBER(20,4) default 0,
+ issuesalary NUMBER(20,4) default 0,
+ createempno VARCHAR2(10) default '',
+ createdate VARCHAR2(8) default '',
+ createtime VARCHAR2(6) default '',
+ updateempno VARCHAR2(10) default '',
+ updatedate VARCHAR2(8) default '',
+ updatetime VARCHAR2(6) default '',
+ tenurerate NUMBER(10,4)
+)
+tablespace ERPDATA
+ pctfree 10
+ initrans 1
+ maxtrans 255
+ storage
+ (
+  initial 64K
+  next 1M
+  minextents 1
+  maxextents unlimited
+ )
+;