How do I modify a MySQL column to allow NULL

Question

MySQL 5 0 45  What is the syntax to alter a table to allow a column to be null  alternately what s wrong with this   ALTER mytable MODIFY mycolumn varchar 255  null    I interpreted the manual as  just run the above and it would recreate the column  this time allowing null  The server is telling me I have syntactical errors  I just don t see them

User · Accepted Answer

You want the following   ALTER TABLE mytable MODIFY mycolumn VARCHAR 255     Columns are nullable by default   As long as the column is not declared UNIQUE or NOT NULL  there shouldn t be any problems

User · Answer

My solution is the same as  Krishnrohit   ALTER TABLE  table  CHANGE  column current name   new column name  DATETIME NULL    I actually had the column set as NOT NULL but with the above query it was changed to NULL   P S  I know this an old thread but nobody seems to acknowledge that CHANGE is also correct

User · Answer

Under some circumstances  if you get  ERROR 1064  42000   You have an error in your SQL syntax       you need to do  ALTER TABLE mytable MODIFY mytable mycolumn varchar 255

User · Answer

Your syntax error is caused by a missing  table  in the query  ALTER TABLE mytable MODIFY mycolumn varchar 255  null

User · Answer

My solution   ALTER TABLE table name CHANGE column name column name type DEFAULT NULL   For example   ALTER TABLE SCHEDULE CHANGE date date DATETIME DEFAULT NULL

User · Answer

Your syntax error is caused by a missing  table  in the query  ALTER TABLE mytable MODIFY mycolumn varchar 255  null

User · Answer

Use  ALTER TABLE mytable MODIFY mycolumn VARCHAR 255

User · Answer

Your syntax error is caused by a missing  table  in the query  ALTER TABLE mytable MODIFY mycolumn varchar 255  null

User · Answer

Your syntax error is caused by a missing  table  in the query  ALTER TABLE mytable MODIFY mycolumn varchar 255  null

User · Answer

My solution   ALTER TABLE table name CHANGE column name column name type DEFAULT NULL   For example   ALTER TABLE SCHEDULE CHANGE date date DATETIME DEFAULT NULL

User · Answer

My solution is the same as  Krishnrohit   ALTER TABLE  table  CHANGE  column current name   new column name  DATETIME NULL    I actually had the column set as NOT NULL but with the above query it was changed to NULL   P S  I know this an old thread but nobody seems to acknowledge that CHANGE is also correct

User · Answer

Use  ALTER TABLE mytable MODIFY mycolumn VARCHAR 255

User · Answer

Under some circumstances  if you get  ERROR 1064  42000   You have an error in your SQL syntax       you need to do  ALTER TABLE mytable MODIFY mytable mycolumn varchar 255

[mysql] How do I modify a MySQL column to allow NULL?

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