Shulou(Shulou.com)06/01 Report--

Basic query

/ *

Syntax:

Select Select, filter, View

Similar to System.out.println ("...") Printing

Features:

1. The query list can be: fields, constants, expressions, functions in the table

2. The result of the query is a virtual table

, /

You can print the name directly by clicking on the information name in the table on the left

Check the code f12 to standardize the style

Query a single field in the table to from to specify the table

SELECT last_name FROM employees

Multiple fields in a query table, separated by commas

SELECT last_name,salary,email FROM employees

Query all fields in the table

# the information name in the first click table is printed directly to the code

SELECT `first_ name`, `last_ name`, `email`, `salary`from employees

# second, select * (asterisk) from table name

SELECT * (asterisk) FROM employees

(the symbol to the left of 1) is an emphasis mark, not a single quotation mark, which is used to distinguish a field name from a keyword, plus an emphasis to indicate the field name

The selected code can be executed by selecting the mouse

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