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mysql [2013/04/17 01:36] – created javapimpmysql [2023/08/18 18:15] (current) – external edit 127.0.0.1
Line 5: Line 5:
 </code> </code>
  
-====== List Databases ======+====== List Users ====== 
 + 
 +<code sql> 
 +mysql> SELECT User FROM mysql.user; 
 +</code> 
 + 
 +====== Databases ====== 
 + 
 +===== List Databases =====
  
 <code sql> <code sql>
Line 11: Line 19:
 </code> </code>
  
-====== List Users ======+===== Change/Select Database =====
  
 <code sql> <code sql>
-mysql> SELECT User FROM mysql.user;+mysql> use <database>; 
 +</code> 
 + 
 +====== Tables ====== 
 + 
 +===== List Tables ===== 
 + 
 +<code sql> 
 +mysql> show tables; 
 +</code> 
 + 
 +===== List Table Columns ===== 
 + 
 +<code sql> 
 +mysql> SHOW COLUMNS FROM <table>; 
 +</code> 
 + 
 +====== VARCHAR ====== 
 + 
 +The max length of varchar in MySQL is 64KB 
 + 
 +<code sql> 
 +VARCHAR(65535) 
 +</code> 
 + 
 +Lower with a multi-byte character set 
 + 
 +<code sql> 
 +VARCHAR(21844) CHARACTER SET utf8 
 +</code> 
 + 
 +====== Execute SQL File ====== 
 + 
 +<code sql> 
 +mysql> source '/<path>/<to>/<file>.sql'; 
 +</code> 
 + 
 +====== Indexes ====== 
 + 
 +===== Add Index ===== 
 + 
 +<code sql> 
 +mysql> ALTER TABLE <table> ADD INDEX <index> (<column>); 
 +</code> 
 + 
 +===== Show Indexes ===== 
 + 
 +<code sql> 
 +mysql> show index from <table>; 
 +</code> 
 + 
 +===== Drop Index ===== 
 + 
 +<code sql> 
 +mysql> alter table <table> drop index <index>; 
 +</code> 
 + 
 +====== Insert ====== 
 + 
 +===== Insert or Update ===== 
 + 
 +<code sql> 
 +mysql> INSERT INTO <table> (field1, field2, field3) VALUES ('value1', 'value2','value3') ON DUPLICATE KEY UPDATE field1='value1', field2='value2', field3='value3';
 </code> </code>
  
mysql.1366162618.txt.gz · Last modified: 2023/08/18 18:15 (external edit)