2 files changed, 81 insertions, 0 deletions
diff --git a/mysql-test/t/func_math.test b/mysql-test/t/func_math.test
index 4c2d7921593..bb9e46c4378 100644
--- a/mysql-test/t/func_math.test
+++ b/mysql-test/t/func_math.test
@@ -587,6 +587,44 @@ INSERT INTO t1 VALUES (1),(2);
 SELECT STDDEV_SAMP(ROUND('0', 309)) FROM t1;
 DROP TABLE t1;
 
+
+--echo #
+--echo # MDEV-20495 Assertion `precision > 0' failed in decimal_bin_size upon CREATE .. SELECT with zerofilled decimal
+--echo #
+
+--echo # Testing that dyadic arithmetic operations are symmetric
+--echo # for (+1) and (-1) and produce the same length in CONCAT(),
+--echo # because (+1) and (-1) have the same data type: signed int.
+
+CREATE TABLE t1 AS SELECT
+  CONCAT(+1%2.0),
+  CONCAT(-1%2.0),
+  CONCAT(+1/2.0),
+  CONCAT(-1/2.0),
+  CONCAT(+1*2.0),
+  CONCAT(-1*2.0),
+  CONCAT(+1+2.0),
+  CONCAT(-1+2.0),
+  CONCAT(+1-2.0),
+  CONCAT(-1-2.0);
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT
+  CONCAT(+1%2),
+  CONCAT(-1%2),
+  CONCAT(+1/2),
+  CONCAT(-1/2),
+  CONCAT(+1*2),
+  CONCAT(-1*2),
+  CONCAT(+1+2),
+  CONCAT(-1+2),
+  CONCAT(+1-2),
+  CONCAT(-1-2);
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 5.5 tests
 --echo #
diff --git a/mysql-test/t/type_newdecimal.test b/mysql-test/t/type_newdecimal.test
index 03e55831972..9b1beeb3f51 100644
--- a/mysql-test/t/type_newdecimal.test
+++ b/mysql-test/t/type_newdecimal.test
@@ -1625,6 +1625,49 @@ SHOW CREATE TABLE t1;
 DROP TABLE t1;
 
 --echo #
+--echo # MDEV-20495 Assertion `precision > 0' failed in decimal_bin_size upon CREATE .. SELECT with zerofilled decimal
+--echo #
+
+CREATE TABLE t1 (d DECIMAL(1,0) ZEROFILL);
+CREATE TABLE t2 AS SELECT 0 MOD d AS f FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (d DECIMAL(1,0) UNSIGNED);
+CREATE TABLE t2 AS SELECT 0 MOD d AS f FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE IF EXISTS t1,t2;
+
+CREATE TABLE t1 (d DECIMAL(1,0) ZEROFILL);
+CREATE TABLE t2 AS SELECT CAST(0 AS UNSIGNED) MOD d AS f FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (d DECIMAL(1,0) UNSIGNED);
+CREATE TABLE t2 AS SELECT CAST(0 AS UNSIGNED) MOD d AS f FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t1,t2;
+
+--echo #
+--echo # MDEV-20560 Assertion `precision > 0' failed in decimal_bin_size upon SELECT with MOD short unsigned decimal
+--echo #
+
+CREATE TABLE t1 (a DECIMAL(1,0) UNSIGNED);
+INSERT INTO t1 VALUES (1.0),(2.0);
+SELECT DISTINCT 1 MOD a FROM t1;
+CREATE TABLE t2 AS SELECT DISTINCT 1 MOD a AS f FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (a DECIMAL(1,0) UNSIGNED);
+INSERT INTO t1 VALUES (1.0),(2.0);
+SELECT DISTINCT 1 MOD a FROM t1;
+CREATE TABLE t2 AS SELECT DISTINCT CAST(1 AS UNSIGNED) MOD a AS f FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t1, t2;
+
+
+--echo #
 --echo # End of 5.5 tests
 --echo #