MYSQL如果列不存在，如何更改表

Question

I am using SQL which doesnt support INFORMATION_SCHEMA.COLUMNS. My code, which doesnt work

ALTER TABLE Report ADD IF NOT EXISTS LastName CHAR(25);

this works

ALTER TABLE Report ADD LastName CHAR(25);

which part is wrong?

IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.COLUMNS 
               WHERE TABLE_NAME  = 'Report' AND COLUMN_NAME = 'LastName' ) 
    ALTER TABLE 'Report' ADD 'LastName' CHAR(25);

Answer 1

You need to quote the object names in the statement.

IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.COLUMNS 
           WHERE TABLE_NAME  = 'Report' AND COLUMN_NAME = 'LastName' ) 
ALTER TABLE MLReport ADD LastName CHAR(25);