SHOW Statements | District | char(20) | NO | | | | | Population | int(11) | NO | | 0 | | +-------------+----------+------+-----+---------+----------------+ An alternative to  tbl_name  FROM  db_name  syntax is  db_name.tbl_name . These two statements are equivalent: SHOW COLUMNS FROM mytable FROM mydb; SHOW COLUMNS FROM mydb.mytable; The optional  EXTENDED  keyword causes the output to include information about hidden columns that MySQL uses internally and are not accessible by users. The optional  FULL  keyword causes the output to include the column collation and comments, as well as the privileges you have for each column. The  LIKE  clause, if present, indicates which column names to match. The  WHERE  clause can be given to select rows using more general conditions, as discussed in Section 26.8, “Extensions to SHOW Statements” . The data types may differ from what you expect them to be based on a  CREATE TABLE  statement because MySQL sometimes changes data types when you create or alter a table. The conditions under which this occurs are described in Section 13.1.20.7, “Silent Column Specification Changes” . SHOW COLUMNS  displays the following values for each table column: The name of the column. The column data type. The collation for nonbinary string columns, or  NULL  for other columns. This value is displayed only if you use the  FULL  keyword. The column nullability. The value is  YES  if  NULL  values can be stored in the column,  NO  if not. Whether the column is indexed: • Field • Type • Collation • Null • Key •If  Key  is empty, the column either is not indexed or is indexed only as a secondary column in a multiple-column, nonunique index. •If  Key  is  PRI , the column is a  PRIMARY KEY  or is one of the columns in a multiple-column  PRIMARY KEY . •If  Key  is  UNI , the column is the first column of a  UNIQUE  index. (A  UNIQUE  index permits multiple NULL  values, but you can tell whether the column permits  NULL  by checking the  Null  field.) •If  Key  is  MUL , the column is the first column of a nonunique index in which multiple occurrences of a given value are permitted within the column. 2916