How does MySQL modify the character set of a table and the character set of a field?

How does MySQL modify the character set of a table and the character set of a field? If you want to change the character set of the table's default character set and all character columns to a new one, use the following statement: alter table tbl_name convert to character set charset_name; warning: the above operation is to convert column values in the character set. If you have a column in a character set (such as gb2312), but the stored values use other incompatible character sets (such as utf8 ), the operation will not get the expected results. In this case, you must perform the following operations on each column: alter table t1 CHANGE c1 c1 BLOB; alter table t1 CHANGE c1 c1 text character set utf8; the reason is: conversion from a BLOB column or to a BLOB column does not occur. If you specify convert to character set in BINARY format, the CHAR, VARCHAR, and TEXT columns are converted TO their corresponding BINARY string types (BINARY, VARBINARY, BLOB ). This means that these columns will no longer have character sets, and subsequent convert to operations will not work on them. If you only change the default character set of a TABLE, use the following statement: alter table tbl_name default character set charset_name; DEFAULT is optional. When a new column is added to a TABLE, if no character set is specified, the default character set is used (for example, when alter table... ADD column ). Alter table... default character set is equivalent to alter table... character set. Only the default table character set is modified.