[fix](planner) ctas should not change any meta of column in source ta…

…ble (#24767)

if previous PR #22770. we try to fix incorrect nullable in target table.
However we changed nullable info of column in source table unexpectly

fe/fe-core/src/main/java/org/apache/doris/analysis/CreateTableAsSelectStmt.java

@@ -17,6 +17,7 @@
 
 package org.apache.doris.analysis;
 
+import org.apache.doris.catalog.Column;
 import org.apache.doris.catalog.ScalarType;
 import org.apache.doris.catalog.Type;
 import org.apache.doris.common.Config;
@@ -82,8 +83,9 @@ public void analyze(Analyzer analyzer) throws UserException {
  Preconditions.checkArgument(outputs.size() == queryStmt.getResultExprs().size());
  for (int i = 0; i < outputs.size(); ++i) {
  if (queryStmt.getResultExprs().get(i).getSrcSlotRef() != null) {
- queryStmt.getResultExprs().get(i).getSrcSlotRef().getColumn()
- .setIsAllowNull(outputs.get(i).isNullable());
+ Column columnCopy = new Column(queryStmt.getResultExprs().get(i).getSrcSlotRef().getColumn());
+ columnCopy.setIsAllowNull(outputs.get(i).isNullable());
+ queryStmt.getResultExprs().get(i).getSrcSlotRef().getDesc().setColumn(columnCopy);
  }
  if (Config.enable_date_conversion) {
  if (queryStmt.getResultExprs().get(i).getType() == Type.DATE) {

regression-test/suites/ddl_p0/test_ctas.groovy

@@ -230,16 +230,21 @@ suite("test_ctas") {
  sql 'insert into a values(1, \'ww\'), (2, \'zs\');'
  sql 'insert into b values(1, 22);'
 
- sql 'create table c properties("replication_num"="1") as select a.id, a.name, b.age from a left join b on a.id = b.id;'
+ sql 'set enable_nereids_planner=false'
+
+ sql 'create table c properties("replication_num"="1") as select b.id, a.name, b.age from a left join b on a.id = b.id;'
 
- String desc = sql 'desc c'
- assertTrue(desc.contains('Yes'))
+ String descC = sql 'desc c'
+ assertTrue(descC.contains('Yes'))
+ String descB = sql 'desc b'
+ assertTrue(descB.contains('No'))
+
  sql '''create table test_date_v2 
  properties (
  "replication_num"="1"
  ) as select to_date('20250829');
  '''
- desc = sql 'desc test_date_v2'
+ String desc = sql 'desc test_date_v2'
  assertTrue(desc.contains('Yes'))
  } finally {
  sql 'drop table a'