danny0405 commented on a change in pull request #1474: [CALCITE-3370] Add NULL
direction emulation for MSSQL
URL: https://github.com/apache/calcite/pull/1474#discussion_r327902744
##########
File path:
core/src/main/java/org/apache/calcite/sql/dialect/MssqlSqlDialect.java
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@@ -61,6 +68,44 @@ public MssqlSqlDialect(Context context) {
top = context.databaseMajorVersion() < 11;
}
+ /**
+ * Emulate null FIRST/LAST with case statements.
+ */
+ @Override public SqlNode emulateNullDirection(SqlNode node, boolean
nullsFirst,
+ boolean desc) {
+ //Default ordering preserved
+ if (nullCollation.isDefaultOrder(nullsFirst, desc)) {
+ return null;
+ }
+
+ //Grouping node should preserve grouping, no emulation needed
+ if (node.getKind() == SqlKind.GROUPING) {
Review comment:
Left a whitespace between comment content and `//`
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