MySQL基礎：搭建bc網站sql執行錯誤時的控制方式

行語句的正常執行

搭建bc網站q<277.03.4.83.6>

比如執行多條正常執行的語句，示例命令如下所示：

  select version();

  select "Hello LiuMiao" as "Greetings";

  select 20+22 as Result;

使用HereDocument方式執行如下所示：

liumiaocn:~ liumiao$ mysql -uroot -proot <<EOF

>   select version();

>   select "Hello LiuMiao" as "Greetings";

>   select 20+22 as Result;

> EOF

mysql: [Warning] Using a password on the command line interface can be insecure.

version()

8.0.11

Greetings

Hello LiuMiao

Result

42

liumiaocn:~ liumiao$ 

多行語句中間出錯時的缺省動作

Oracle多行語句執行出錯時在sqlplus中會繼續執行，而在mysql控制臺中會怎樣呢？我們可以在上述語句中添加一行錯誤的語法或者命令來進行驗證：

mysql -uroot -proot <<EOF

  select version();

  errorcommand;

  select "Hello LiuMiao" as "Greetings";

  select 20+22 as Result;

EOF

執行結果如下所示

liumiaocn:~ liumiao$ mysql -uroot -proot <<EOF

>   select version();

>   errorcommand;

>   select "Hello LiuMiao" as "Greetings";

>   select 20+22 as Result;

> EOF

mysql: [Warning] Using a password on the command line interface can be insecure.

version()

8.0.11

ERROR 1064 (42000) at line 2: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'errorcommand' at line 1

liumiaocn:~ liumiao$ 

可以看到，缺省情況下碰到錯誤就停下來了。

WHENEVER SQLERROR

在oracle中通過WHENEVER SQLERROR來進行控制。語法如下所示

WHENEVER SQLERROR {EXIT [SUCCESS | FAILURE | WARNING | n | variable | :BindVariable] [COMMIT | ROLLBACK] | CONTINUE [COMMIT | ROLLBACK | NONE]}