str2decimal: don't return a negative zero

mysql-test/r/type_decimal.result

@@ -221,7 +221,6 @@ drop  table t1;
 create table t1 (a decimal(10,2) unsigned);
 insert into t1 values ("0.0"),("-0.0"),("+0.0"),("01.0"),("+01.0"),("-01.0");
 Warnings:
-Warning	1264	Out of range value for column 'a' at row 2
 Warning	1264	Out of range value for column 'a' at row 6
 insert into t1 values ("-.1"),("+.1"),(".1");
 Warnings:
@@ -280,7 +279,6 @@ drop  table t1;
 create table t1 (a decimal(10,2) zerofill);
 insert into t1 values ("0.0"),("-0.0"),("+0.0"),("01.0"),("+01.0"),("-01.0");
 Warnings:
-Warning	1264	Out of range value for column 'a' at row 2
 Warning	1264	Out of range value for column 'a' at row 6
 insert into t1 values ("-.1"),("+.1"),(".1");
 Warnings:
@@ -1012,6 +1010,9 @@ SELECT COLUMN_NAME, DATA_TYPE, COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE
 COLUMN_NAME	DATA_TYPE	COLUMN_TYPE
 a	decimal	decimal(10,2)/*old*/
 DROP TABLE t1dec102;
+select cast('-0.0' as decimal(5,1)) < 0;
+cast('-0.0' as decimal(5,1)) < 0
+0
 #
 # End of 5.5 tests
 #

mysql-test/t/type_decimal.test

@@ -604,6 +604,11 @@ SHOW COLUMNS FROM t1dec102;
 SELECT COLUMN_NAME, DATA_TYPE, COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='t1dec102';
 DROP TABLE t1dec102;
 
+#
+# MDEV-10552 equality operation on cast of the value "-0.0" to decimal not working
+#
+select cast('-0.0' as decimal(5,1)) < 0;
+
 --echo #
 --echo # End of 5.5 tests
 --echo #

storage/tokudb/mysql-test/tokudb/r/type_decimal.result

@@ -222,7 +222,6 @@ drop  table t1;
 create table t1 (a decimal(10,2) unsigned);
 insert into t1 values ("0.0"),("-0.0"),("+0.0"),("01.0"),("+01.0"),("-01.0");
 Warnings:
-Warning	1264	Out of range value for column 'a' at row 2
 Warning	1264	Out of range value for column 'a' at row 6
 insert into t1 values ("-.1"),("+.1"),(".1");
 Warnings:
@@ -281,7 +280,6 @@ drop  table t1;
 create table t1 (a decimal(10,2) zerofill);
 insert into t1 values ("0.0"),("-0.0"),("+0.0"),("01.0"),("+01.0"),("-01.0");
 Warnings:
-Warning	1264	Out of range value for column 'a' at row 2
 Warning	1264	Out of range value for column 'a' at row 6
 insert into t1 values ("-.1"),("+.1"),(".1");
 Warnings:

strings/decimal.c

@@ -928,6 +928,8 @@ internal_str2dec(const char *from, decimal_t *to, char **end, my_bool fixed)
         error= decimal_shift(to, (int) exponent);
     }
   }
+  if (to->sign && decimal_is_zero(to))
+    to->sign= 0;
   return error;
 
 fatal_error: