zhengruifeng commented on code in PR #45796:
URL: https://github.com/apache/spark/pull/45796#discussion_r1547242375
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sql/core/src/main/scala/org/apache/spark/sql/Column.scala:
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@@ -1222,6 +1222,43 @@ class Column(val expr: Expression) extends Logging {
*/
def cast(to: String): Column = cast(CatalystSqlParser.parseDataType(to))
+ /**
+ * Casts the column to a different data type and the result is null on
failure.
+ * {{{
+ * // Casts colA to IntegerType.
+ * import org.apache.spark.sql.types.IntegerType
+ * df.select(df("colA").try_cast(IntegerType))
+ *
+ * // equivalent to
+ * df.select(df("colA").try_cast("int"))
+ * }}}
+ *
+ * @group expr_ops
+ * @since 4.0.0
+ */
+ def try_cast(to: DataType): Column = withExpr {
+ val cast = Cast(
+ child = expr,
+ dataType = CharVarcharUtils.replaceCharVarcharWithStringForCast(to),
+ evalMode = EvalMode.TRY)
+ cast.setTagValue(Cast.USER_SPECIFIED_CAST, ())
Review Comment:
https://github.com/apache/spark/blob/f18d945af7b69fbc89b38b9ca3ca79263b0881ed/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Cast.scala#L182-L185
I guess it is used to distinguish between user calls and internal calls.
Seems we never support it in Spark Connect though
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