即使存在使用键列的where子句，Delete也失败

Question

我是mySQL的新手，在学习连接的同时，我尝试使用左连接、右连接和完全外部连接来创建一个完全连接。然后我意识到我的一个原始表（表t2)有一个空行。

当尝试删除它时，我得到错误：错误代码：1175。您正在使用安全更新模式，并且试图更新一个没有使用键列禁用安全模式的WHERE的表，请在Preferences->SQL Editor中切换该选项并重新连接。

create table t1( c1 integer, c2 integer, c3  varchar (10));
create table t2( c1 integer, c2 integer, c3 varchar(10));

insert into t1 values ( 1, 2, "foo"), (2,3, "bar"),(3,8,"random");
insert into t2 values ( 1, 4, "jack"), (2,6,"jill"), (4,9,"hill");
alter table t2 add primary key (c1);
update  t2 set c1 = 3 where c1 = 4; 
delete from t2 where c1 is null;
select * from t1;
select * from t2;
select * from t1 left join t2 on t1.c1=t2.c1 
union
select * from t1 right join t2 on t1.c1=t2.c1;

 delete from t2 where c1 is null;

t1
+------+------+--------+
| c1   | c2   | c3     |
+------+------+--------+
|    1 |    2 | foo    |
|    2 |    3 | bar    |
|    3 |    8 | random |
+------+------+--------+

t2
+----+------+------+
| c1 | c2   | c3   |
+----+------+------+
|  1 |    4 | jack |
|  2 |    6 | jill |
|  3 |    9 | hill |
|NULL| NULL | NULL |
+----+------+------+

t1 union t2
+------+------+--------+------+------+------+
| c1   | c2   | c3     | c1   | c2   | c3   |
+------+------+--------+------+------+------+
|    1 |    2 | foo    |    1 |    4 | jack |
|    2 |    3 | bar    |    2 |    6 | jill |
|    3 |    8 | random |    3 |    9 | hill |
+------+------+--------+------+------+------+

更新：当我使用MySQL命令行时，我没有看到空行，但是当我在Workbench中运行脚本时我看到了它。此外，我更新了我的代码的基础上的答案，但我不能添加图片到现在，因为我是新的，我不允许做添加图片：（，以下是新的代码。

create table t1( c1 integer, c2 integer, c3  varchar (10), primary key(c1));
create table t2( c1 integer, c2 integer, c3 varchar(10),primary key (c1));

insert into t1 values ( 1, 2, "foo"), (2,3, "bar"),(3,8,"random");
insert into t2 values ( 1, 4, "jack"), (2,6,"jill"), (4,9,"hill");
/*alter table t2 add primary key (c1);*/
update  t2 set c1 = 3 where c1 = 4; 
delete from t2 where c1 is null;
select * from t1;
select * from t2;
select * from t1 left join t2 on t1.c1=t2.c1 
union
select * from t1 right join t2 on t1.c1=t2.c1;

Answer 1

只需在查询运行之前使用workbench查询编辑器中的以下代码

SET SQL_SAFE_UPDATES = 0;