cloud-fan commented on code in PR #48621:
URL: https://github.com/apache/spark/pull/48621#discussion_r1814540503
##########
sql/core/src/main/scala/org/apache/spark/sql/jdbc/MsSqlServerDialect.scala:
##########
@@ -88,11 +88,29 @@ private case class MsSqlServerDialect() extends JdbcDialect
with NoLegacyJDBCErr
case e: Predicate => e.name() match {
case "=" | "<>" | "<=>" | "<" | "<=" | ">" | ">=" =>
val Array(l, r) = e.children().map {
- case p: Predicate => s"CASE WHEN ${inputToSQL(p)} THEN 1 ELSE 0
END"
+ case p: Predicate => inputToCaseWhenSQL(p)
case o => inputToSQL(o)
}
visitBinaryComparison(e.name(), l, r)
- case "CASE_WHEN" =>
visitCaseWhen(expressionsToStringArray(e.children())) + " = 1"
+ case "CASE_WHEN" =>
+ // Since MsSqlServer cannot handle boolean expressions inside
+ // a CASE WHEN, it is necessary to convert those to an IIF
+ // expression that will return 1 or 0 depending on the result.
+ // Example:
+ // In: ... CASE WHEN a = b THEN c = d ...
+ // Out: ... CASE WHEN a = b THEN IIF(c = d, 1, 0) ...
+
+ // grouped turns Array[Expression] to Array[Array[Expression]]
+ // with a len of max 2 (final one will have only one)
+ val stringArray = e.children().grouped(2).flatMap { arr =>
+ arr.dropRight(1).map(inputToSQL) :+
+ (arr.last match {
+ case p: Predicate if p.name() != "ALWAYS_TRUE" && p.name()
!= "ALWAYS_FALSE" =>
Review Comment:
> ALWAYS_TRUE gets translated to 1
Where does it happen?
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
