USE db_name
The USE db_name statement tells MySQL to use the db_name database as the default database for subsequent queries. The database remains current until the end of the session or until another USE statement is issued:
mysql> USE db1; mysql> SELECT COUNT(*) FROM mytable; # selects from db1.mytable mysql> USE db2; mysql> SELECT COUNT(*) FROM mytable; # selects from db2.mytable
Making a particular database current by means of the USE statement does not preclude you from accessing tables in other databases. The following example accesses the author table from the db1 database and the editor table from the db2 database:
mysql> USE db1; mysql> SELECT author_name,editor_name FROM author,db2.editor -> WHERE author.editor_id = db2.editor.editor_id;
{DESCRIBE | DESC} tbl_name {col_name | wild}
DESCRIBE is a shortcut for SHOW COLUMNS FROM. See Section 4.5.6.1.
DESCRIBE provides information about a table’s columns. col_name
may be a column name or a string containing the SQL %
and _
wildcard characters.
If the column types are different from what you expect them to be based on a CREATE TABLE statement, note that MySQL sometimes changes column types. See Section 6.5.3.1.
This statement is provided for Oracle compatibility.
The SHOW statement provides similar information. See Section 4.5.6.
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