hotline #16240 : modify patch to test if column exist before alter table

cosmogramme/sql/patch/patch_219.sql

-alter table bib_c_site add column MAIL_SUGGESTIONS varchar(150) null default null AFTER MAIL;
+select count(*) into @exist from information_schema.columns 
+where table_schema = database()
+and COLUMN_NAME= 'MAIL_SUGGESTIONS'
+and table_name = 'bib_c_site';
+
+set @query =  IF(@exist <= 0 , 'ALTER TABLE bib_c_site add column MAIL_SUGGESTIONS varchar(150) null default null AFTER MAIL','select \'Column Exists\' status');
+
+prepare stmt from @query;
+
+EXECUTE stmt;