High-frequency SQL statement Summary

2. Create a database CREATE Database name/* DEFAULT CHARSET UTF8 COLLATE utf8_general_ci;*/

4. Deleting a database DROP DATABASES database name;

6. Show Database list SHOW DATABASES;

8. Show Table List SHOW TABLES;

10. Switch Database Use database name;

12. Build Table CREATE TABLE ' table1 ' (' ID ' INT (3) NOT NULL auto_increment, ' user_name ' VARCHAR (+) ' NOT NULL, ' password ' CHAR (+) ' NOT NULL , PRIMARY KEY (' id ')) auto_increment=1 engine=myisam DEFAULT CHARSET UTF8 COLLATE utf8_general_ci;
14. Delete a table DROP TABLE table1;
16. Clear Table (The index data is cleared) TRUNCATE TABLE table1;
18. Modify table structure
    1. Add primary key ALTER table  ' table1 '  add& nbsp Primary key (field name);
    2. Remove the add from the primary key and replace it with a drop
    3. add unique key alter table  ' table1 '  add unique key (field name);
    4. add normal key alter table  ' table1 '  add index (field name);
    5. add field alter table  ' table1 '  ADD  ' field name '  int (3)/* (After ' field Name 2 ') after which field */;
    6. Modify field cannot be changed to field name alter table  ' table1 '  MODIFY  ' field name '  varchar (a)  not NULL
    7. change field name alter table  ' table1 '  CHANGE  ' field name '   ' new field name '  varchar (()  not NULL
    8. Delete field alter table  ' table1 '  DROP  ' ziduan1 ';
20. modifying table Data
    1. Add: INSERT INTO ' table name ' (' Field name 1 ', ' Field 2 ' ...) values (' Value 1 ', ' Value 2 ' ...);
    2. Delete: Delete from ' table name ' where ' Field 1 ' > ' and/*or*/' Field 2 ' < ' 100 ';
    3. Change: Update ' table name ' Set ' field 1 ' = ' value 1 ', ' field 2 ' = ' value 2 ' .../*where condition */
    4. Check: Select ' Field 1 ', ' Field 2 ' ... from ' table name '/*where condition */

High-frequency SQL statement Summary