INTERVAL support, date pseudo literals TIMESTAMP and TIME literals.

The interval was not allowed to be a column data type.
With this patch we add this support.

We add support for the pseudo literals
CURRENT_TIME, CURRENT_TIMESTAMP, CURRENT_DATE.

Also, we add support for TIMESTAMP and TIME literals.
The user can now explicitly set the type of the string value it follows
with TIMESTAMP 'value' and TIME 'value.

DATE was already supported.

Author: kchasapis

src/parser/bison_parser.cpp

@@ -210,6 +210,7 @@
 
 /* SQL Keywords */
 %token DEALLOCATE PARAMETERS INTERSECT TEMPORARY TIMESTAMP
+%token CURRENT_TIMESTAMP CURRENT_DATE CURRENT_TIME
 %token DISTINCT NVARCHAR RESTRICT TRUNCATE ANALYZE BETWEEN
 %token CASCADE COLUMNS CONTROL DEFAULT EXECUTE EXPLAIN ENCODING
 %token INTEGER NATURAL PREPARE SCHEMAS CHARACTER_VARYING REAL DECIMAL SMALLINT BIGINT
@@ -265,6 +266,7 @@
 %type <expr>                   expr operand scalar_expr unary_expr binary_expr logic_expr exists_expr extract_expr cast_expr
 %type <expr>                   function_expr between_expr expr_alias param_expr
 %type <expr>                   column_name literal int_literal num_literal string_literal bool_literal date_literal interval_literal
+%type <expr>                   timestamp_literal time_literal current_timestamp current_date current_time
 %type <expr>                   comp_expr opt_where join_condition opt_having case_expr case_list in_expr hint
 %type <expr>                   array_expr array_index null_literal extended_literal casted_extended_literal
 %type <limit>                  opt_limit opt_top
@@ -643,7 +645,7 @@ column_type : BIGINT { $$ = ColumnType{DataType::BIGINT}; }
 | BOOLEAN { $$ = ColumnType{DataType::BOOLEAN}; }
 | CHAR '(' INTVAL ')' { $$ = ColumnType{DataType::CHAR, $3}; }
 | CHARACTER_VARYING '(' INTVAL ')' { $$ = ColumnType{DataType::VARCHAR, $3}; }
-| DATE { $$ = ColumnType{DataType::DATE}; };
+| DATE { $$ = ColumnType{DataType::DATE}; }
 | DATETIME { $$ = ColumnType{DataType::DATETIME}; }
 | DECIMAL opt_decimal_specification {
   $$ = ColumnType{DataType::DECIMAL, 0, $2->first, $2->second};
@@ -653,6 +655,7 @@ column_type : BIGINT { $$ = ColumnType{DataType::BIGINT}; }
 | FLOAT { $$ = ColumnType{DataType::FLOAT}; }
 | INT { $$ = ColumnType{DataType::INT}; }
 | INTEGER { $$ = ColumnType{DataType::INT}; }
+| INTERVAL { $$ = ColumnType{DataType::INTERVAL}; }
 | LONG { $$ = ColumnType{DataType::LONG}; }
 | REAL { $$ = ColumnType{DataType::REAL}; }
 | SMALLINT { $$ = ColumnType{DataType::SMALLINT}; }
@@ -1008,7 +1011,7 @@ extended_literal : literal {
   }
   $$ = $1;
 }
-| '-' num_literal { $$ = Expr::makeOpUnary(kOpUnaryMinus, $2); };
+| '-' num_literal { $$ = Expr::makeOpUnary(kOpUnaryMinus, $2); }
 | '-' interval_literal { $$ = Expr::makeOpUnary(kOpUnaryMinus, $2); };
 
 expr_alias : expr opt_alias {
@@ -1139,7 +1142,8 @@ column_name : IDENTIFIER { $$ = Expr::makeColumnRef($1); }
 | '*' { $$ = Expr::makeStar(); }
 | IDENTIFIER '.' '*' { $$ = Expr::makeStar($1); };
 
-literal : string_literal | bool_literal | num_literal | null_literal | date_literal | interval_literal | param_expr;
+literal : string_literal | bool_literal | num_literal | null_literal | date_literal | interval_literal | param_expr
+| timestamp_literal | time_literal | current_timestamp | current_date | current_time;
 
 string_literal : STRING { $$ = Expr::makeLiteral($1); };
 
@@ -1164,6 +1168,14 @@ date_literal : DATE STRING {
   $$ = Expr::makeDateLiteral($2);
 };
 
+timestamp_literal : TIMESTAMP STRING {
+  $$ = Expr::makeTimestampLiteral($2);
+};
+
+time_literal : TIME STRING {
+  $$ = Expr::makeTimeLiteral($2);
+};
+
 interval_literal : INTVAL duration_field { $$ = Expr::makeIntervalLiteral($1, $2); }
 | INTERVAL STRING datetime_field {
   int duration{0}, chars_parsed{0};
@@ -1176,19 +1188,22 @@ interval_literal : INTVAL duration_field { $$ = Expr::makeIntervalLiteral($1, $2
   free($2);
   $$ = Expr::makeIntervalLiteral(duration, $3);
 }
+| INTERVAL INTVAL datetime_field {
+  $$ = Expr::makeIntervalLiteral($2, $3);
+}
 | INTERVAL STRING {
   int duration{0}, chars_parsed{0};
   // 'seconds' and 'minutes' are the longest accepted interval qualifiers (7 chars) + null byte
   char unit_string[8];
   // If the whole string is parsed, chars_parsed points to the terminating null byte after the last character
   if (sscanf($2, "%d %7s%n", &duration, unit_string, &chars_parsed) != 2 || $2[chars_parsed] != 0) {
     free($2);
-    yyerror(&yyloc, result, scanner, "Found incorrect interval format. Expected format: INTEGER INTERVAL_QUALIIFIER");
+    yyerror(&yyloc, result, scanner, "Found incorrect interval format. Expected format: INTEGER INTERVAL_QUALIFIER");
     YYERROR;
   }
   free($2);
 
-  DatetimeField unit;
+  DatetimeField unit = kDatetimeNone;
   if (strcasecmp(unit_string, "second") == 0 || strcasecmp(unit_string, "seconds") == 0) {
     unit = kDatetimeSecond;
   } else if (strcasecmp(unit_string, "minute") == 0 || strcasecmp(unit_string, "minutes") == 0) {
@@ -1214,6 +1229,12 @@ param_expr : '?' {
   yyloc.param_list.push_back($$);
 };
 
+current_timestamp : CURRENT_TIMESTAMP { $$ = Expr::makeCurrentTimestamp(); };
+
+current_date : CURRENT_DATE { $$ = Expr::makeCurrentDate(); };
+
+current_time : CURRENT_TIME { $$ = Expr::makeCurrentTime(); };
+
 /******************************
  * Table
  ******************************/