Mys data operation F-rich

2. Add a row of data: INSERT into table name (List of column names: can be omitted) values (matches previous column name lists)
4. Import data for a column from another table: Inset into table name (column name) Select column name from table name
6. Modify the data for a row of columns: Update table name set column name = value, column name 1= value 1...where conditional statement; ignore WHERE clause modifies column Name column of entire table
8. Delete a row of data: Delete from table name where conditional clause, Delete self-growth will not be restored, next time the data is inserted, it will grow, because the log will be recorded, the data will be restored
10. Initialize table: TRUNCATE TABLE name
12. Query data: Classification: 1, Projection operations: Specify the query structure to display those columns select *| column name from table Name 2, select action: Make those rows appear in the results where 3, arrange operations: show results in a certain order by
14. Column alias: Column name as custom name
16. Table aliases: Table name as custom name as can be omitted
18. Splicing columns: Select concat (column name, column name) from table name
20. Paging: Select *| list from limit num1,num2; NUM1 starting with NUM1 (integer), displaying num2 (integer) Rows
22. Exclude duplicate data: Select DISTINCT column list from table name; Column Name list as a whole to go heavy
24. Select data: =,<,>,<> equivalent not equal to combination: and or set relationship: in () satisfies parentheses, not in ()

25. Fuzzy Search: SELECT field from table WHERE a field like condition

    1,%: Represents any of 0 or more characters. Can match any type and length of the character, in some cases, if Chinese, please use two percent sign (%).

    For example SELECT * from [user] WHERE u_name like '% three '

    will be u_name for "Zhang San", "Zhang Cat Three", "three-legged Cat", "Tang Sanzang" and so on Have "three" records all find out.

    Also, if you need to find a record of "three" and "cat" in U_name, use the and condition

    SELECT * FROM [user] WHERE u_name like '% three ' and u_name like '% cat% '

    If using SELECT * from [user] WHERE u_name like '% cat% '

    Although can search out "three feet cat", but can not search out the eligible "Zhang Cat three".

    2,_: Represents any single character. Matches a single arbitrary character, which is commonly used to restrict the expression's character-length statement:

    For example SELECT * from [user] WHERE u_name like ' _ Three _ '

    Only find "Tang Sanzang" so u_name for three words and the middle of a word is "three";

    Another example is SELECT * from [user] WHERE u_name like ' three __ ';

    Just find out "three-legged cat" so name is three words and the first word is "three"

Mys data operation F-rich