MySQL 如果MySQL中不存在，如何说创建过程
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how to say create procedure if not exist in MySQL
提问by Frank
I am trying to write a script to create a procedure in MySQL database, but I want to check if it exsit first.
我正在尝试编写一个脚本来在 MySQL 数据库中创建一个过程，但我想先检查它是否存在。
I know how to do it for a table, but when I use the same syntax for stored procedure, it doesn't compile.
我知道如何为表执行此操作，但是当我对存储过程使用相同的语法时，它无法编译。
Does anybody know? Thanks
有人知道吗？谢谢
回答by Cory Klein
Just drop the procedure if it does exist and then re-add it:
如果它确实存在，只需删除该过程，然后重新添加它：
DROP PROCEDURE IF EXISTS my_procedure;
CREATE PROCEDURE my_procedure()
回答by Ben English
SELECT EXISTS(SELECT 1 FROM mysql.proc p WHERE db = 'db_name' AND name = 'stored_proc_name');
So you could do:
所以你可以这样做：
IF NOT EXISTS(SELECT 1 FROM mysql.proc p WHERE db = 'db_name' AND name = 'stored_proc_name') THEN
....
END IF;
回答by robertvoliva
It doesn't exist. We had to write a stored procedure that mimics the same functionality. Basically we create stored procedures by calling a stored procedure that does the "if exists" check.
它不存在。我们必须编写一个模拟相同功能的存储过程。基本上，我们通过调用执行“如果存在”检查的存储过程来创建存储过程。
