The INFORMATION_SCHEMA INNODB_COLUMNS Table • PRTYPE • LEN • HAS_DEFAULT • DEFAULT_VALUE A boolean value indicating whether a column that was added instantly using  ALTER TABLE ... ADD COLUMN  with  ALGORITHM=INSTANT  has a default value. All columns added instantly have a default value, which makes this column an indicator of whether the column was added instantly. The initial default value of a column that was added instantly using  ALTER TABLE ... ADD COLUMN with  ALGORITHM=INSTANT . If the default value is  NULL  or was not specified, this column reports NULL . An explicitly specified non- NULL  default value is shown in an internal binary format. Subsequent modifications of the column default value do not change the value reported by this column. The column length, for example 4 for  INT  and 8 for  BIGINT . For character columns in multibyte character sets, this length value is the maximum length in bytes needed to represent a definition such as VARCHAR( N ) ; that is, it might be  2* N ,  3* N , and so on depending on the character encoding. The  InnoDB  “precise type” , a binary value with bits representing MySQL data type, character set code, and nullability. Example mysql>  SELECT * FROM INFORMATION_SCHEMA.INNODB_COLUMNS where TABLE_ID = 71\G *************************** 1. row *************************** TABLE_ID: 71 NAME: col1 POS: 0 MTYPE: 6 PRTYPE: 1027 LEN: 4 HAS_DEFAULT: 0 DEFAULT_VALUE: NULL *************************** 2. row *************************** TABLE_ID: 71 NAME: col2 POS: 1 MTYPE: 2 PRTYPE: 524542 LEN: 10 HAS_DEFAULT: 0 DEFAULT_VALUE: NULL *************************** 3. row *************************** TABLE_ID: 71 NAME: col3 POS: 2 MTYPE: 1 PRTYPE: 524303 LEN: 10 HAS_DEFAULT: 0 DEFAULT_VALUE: NULL Notes •You must have the  PROCESS  privilege to query this table. •Use the  INFORMATION_SCHEMA COLUMNS  table or the  SHOW COLUMNS  statement to view additional information about the columns of this table, including data types and default values. 4858