MDEV-26698: Incorrect row number upon INSERT .. SELECT from the samebb-10.2-MDEV-26698

table: rows are counted twice

Analysis: When the table we are trying to insert into and the SELECT table
are same for INSERT ... SELECT, rows from the SELECT table are copied into
internal temporary table and then to the INSERT table. We only want to
count the rows when we start inserting into the table.
Fix: Reset the counter to 1 before starting to copy from internal temporary
table to select table and then increment the counter.

1 files changed, 19 insertions, 0 deletions

diff --git a/mysql-test/r/insert_select.result b/mysql-test/r/insert_select.result
index b86c859d0bd..26076eec068 100644
--- a/mysql-test/r/insert_select.result
+++ b/mysql-test/r/insert_select.result
@@ -865,3 +865,22 @@ t2	CREATE TABLE `t2` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1, t2;
 End of 5.5 tests
+#
+# Beginning of 10.2 test
+#
+# MDEV-26698: Incorrect row number upon INSERT .. SELECT from the same
+#             table: rows are counted twice
+#
+CREATE TABLE t1(a TINYINT);
+INSERT INTO t1 VALUES (1), (100);
+INSERT INTO t1 SELECT a*2 FROM t1;
+Warnings:
+Warning	1264	Out of range value for column 'a' at row 2
+TRUNCATE TABLE t1;
+# using ORDER BY
+INSERT INTO t1 VALUES(1), (2), (100), (3);
+INSERT INTO t1 SELECT a*2 FROM t1 ORDER BY a;
+Warnings:
+Warning	1264	Out of range value for column 'a' at row 4
+DROP TABLE t1;
+# End of 10.2 test