Restore support of DATETIME(precision)

h2/src/docsrc/help/help.csv

@@ -2671,11 +2671,12 @@ DATE
 
 "Data Types","TIMESTAMP Type","
 { TIMESTAMP [ ( precisionInt ) ] [ WITHOUT TIME ZONE ]
-    | DATETIME | SMALLDATETIME }
+    | DATETIME [ ( precisionInt ) ] | SMALLDATETIME }
 ","
 The timestamp data type. The format is yyyy-MM-dd hh:mm:ss[.nnnnnnnnn].
 Stored internally as a BCD-encoded date, and nanoseconds since midnight.
 If fractional seconds precision is specified it should be from 0 to 9, 6 is default.
+Fractional seconds precision of SMALLDATETIME is always 0 and cannot be specified.
 
 Mapped to ""java.sql.Timestamp"" (""java.util.Date"" may be used too).
 ""java.time.LocalDateTime"" is also supported on Java 8 and later versions.

h2/src/main/org/h2/command/Parser.java

@@ -4475,6 +4475,20 @@ public class Parser {
                         precision = displaySize = ValueTimestampTimeZone.getDisplaySize(originalScale);
                         break;
                     }
+                } else if (original.equals("DATETIME")) {
+                    if (readIf("(")) {
+                        originalScale = readPositiveInt();
+                        if (originalScale > ValueTime.MAXIMUM_SCALE) {
+                            throw DbException.get(ErrorCode.INVALID_VALUE_SCALE_PRECISION, Integer.toString(originalScale));
+                        }
+                        read(")");
+                        scale = originalScale;
+                        original = original + '(' + originalScale + ')';
+                        precision = displaySize = ValueTimestamp.getDisplaySize(originalScale);
+                    }
+                } else if (original.equals("SMALLDATETIME")) {
+                    scale = 0;
+                    precision = displaySize = ValueTimestamp.getDisplaySize(0);
                 }
             } else if (readIf("(")) {
                 if (!readIf("MAX")) {
@@ -4562,7 +4576,6 @@ public class Parser {
                     Integer.toString(scale), Long.toString(precision));
         }
 
-
         Column column = new Column(columnName, type, precision, scale,
             displaySize, enumerators);
         if (templateColumn != null) {

h2/src/test/org/h2/test/scripts/datatypes/timestamp.sql

@@ -15,7 +15,9 @@ SELECT T1, T2, T1 = T2 FROM TEST;
 > 2010-01-01 10:00:00 2010-01-01 10:00:00 TRUE
 > rows: 1
 
-ALTER TABLE TEST ADD (T3 TIMESTAMP(0), T4 TIMESTAMP(9) WITHOUT TIME ZONE);
+ALTER TABLE TEST ADD (T3 TIMESTAMP(0), T4 TIMESTAMP(9) WITHOUT TIME ZONE,
+    DT1 DATETIME, DT2 DATETIME(0), DT3 DATETIME(9), SDT1 SMALLDATETIME);
+> ok
 
 SELECT COLUMN_NAME, DATA_TYPE, TYPE_NAME, COLUMN_TYPE, NUMERIC_SCALE FROM INFORMATION_SCHEMA.COLUMNS
     WHERE TABLE_NAME = 'TEST' ORDER BY ORDINAL_POSITION;
@@ -25,11 +27,21 @@ SELECT COLUMN_NAME, DATA_TYPE, TYPE_NAME, COLUMN_TYPE, NUMERIC_SCALE FROM INFORM
 > T2          93        TIMESTAMP TIMESTAMP WITHOUT TIME ZONE    6
 > T3          93        TIMESTAMP TIMESTAMP(0)                   0
 > T4          93        TIMESTAMP TIMESTAMP(9) WITHOUT TIME ZONE 9
-> rows (ordered): 4
+> DT1         93        TIMESTAMP DATETIME                       6
+> DT2         93        TIMESTAMP DATETIME(0)                    0
+> DT3         93        TIMESTAMP DATETIME(9)                    9
+> SDT1        93        TIMESTAMP SMALLDATETIME                  0
+> rows (ordered): 8
 
 ALTER TABLE TEST ADD T5 TIMESTAMP(10);
 > exception
 
+ALTER TABLE TEST ADD DT4 DATETIME(10);
+> exception
+
+ALTER TABLE TEST ADD STD2 SMALLDATETIME(1);
+> exception
+
 DROP TABLE TEST;
 > ok