Chapter II using the SQLite database

SQLite database

Features: Lightweight, no installation required. A database corresponds to a file.

-->sqlite3 d:/mydb.db (Create a new mydb.db file under D, open the file if it exists)

-->.databases into the database.

-->.schema Querying all table structures

-->.schema City Query The table structure in the city table//schema Overview n

-->.tables list all the table names

-->.help Viewing command Help

SELECT statement query:

Select field name from table name where filter condition;

Distinct field name to redo the current field

After where the arithmetic operators such as +,-,% can be executed;

After where you can perform comparison operators such as >,<,<>;

Where it can be performed with or non-operational such as And,or;

Limit 5 Query the first 5 data

Limit 5,3 from the sixth row, check 3 data (that is, 6,7,8 line).

Limit 3 offset 5 query from line sixth, check 3 data (that is, 6,7,8 line).

The Order By field name Asc/desc is in the current word Sheng/reverse order.

Like "_abc%"; Start with any single character, the middle is ABC, and then the content is unlimited.

In (A,B,C,D); Satisfies any one of the data in the in.

Between A and B are closed intervals from A to B.

Note: column names, table names are case-insensitive, and the value of the query field is case-sensitive.

such as: where name = "abc"; WHERE name = "ABC";

As an example above, the field name and name are case-insensitive. But ABC and ABC, which are filter conditions, are case-sensitive.

Chapter II using the SQLite database