mysql python 中的语法错误

Question

sql = """
DROP PROCEDURE
IF EXISTS schema_change;

delimiter ';;'
CREATE PROCEDURE schema_change() BEGIN

    if exists (select * from information_schema.columns where table_schema = 
    schema() and table_name = 'selectedairport' and column_name = 'GDP') 
    then
        alter table selectedairport drop column GDP;

    alter table selectedairport add column GDP DOUBLE;

end;;

delimiter ';'


CALL schema_change () ; DROP PROCEDURE
IF EXISTS schema_change ;
"""
cursor6.execute(sql)

但是，这会产生错误：

pymysql.err.ProgrammingError: (1064, "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 'delimiter ';;'\nCREATE PROCEDURE schema_change() BEGIN\n\n if exists (select * f' at line 1")

可能是什么问题？

Answer 1

execute()方法（通常）一次只执行一条命令，所以无法解析脚本，反正不支持DELIMITER；参见 this comment on GitHub。因此，一种解决方案是多次调用：

cursor6.execute("""
DROP PROCEDURE
IF EXISTS schema_change
""")

cursor6.execute("""
CREATE PROCEDURE schema_change() BEGIN

    if exists (select * from information_schema.columns where table_schema = 
    schema() and table_name = 'selectedairport' and column_name = 'GDP') 
    then
        alter table selectedairport drop column GDP;

注意：这里有语法错误，需要进一步补充：

    END IF;

现在像以前一样继续：

    alter table selectedairport add column GDP DOUBLE;

end
""")

cursor6.execute("""
CALL schema_change () 
""")

# Or cursor6.callproc('schema_change')

cursor6.execute("""
DROP PROCEDURE
IF EXISTS schema_change
""")

mysql python 中的语法错误

mysql error syntax in python

python

mysql5

python-3.x