Some common MySQL query table statements

In MySQL, querying tables is one of the most common operations. We need to use different query methods to extract data from the table. Next, we will introduce some common MySQL query table statements.

1. SELECT

SELECT is one of the most important statements in MySQL. It retrieves data from one or more tables and presents the retrieved data in tabular form.

Syntax: SELECT column_name(s) FROM table_name

For example, if you want to retrieve all data from the table named customers, you can use the following statement:

SELECT * FROM customers;

This will return all the data in the table.

2. WHERE

The WHERE clause is used to filter the required data.

Syntax: SELECT column_name(s) FROM table_name WHERE condition

For example, if you only want to select information about people with the last name "Smith" from the customers table, you can use the following statement:

SELECT * FROM customers WHERE last_name = "Smith";

3. ORDER BY

ORDER BY statement is used to sort query results, in ascending or descending order .

Syntax: SELECT column_name(s) FROM table_name ORDER BY column_name(s) ASC|DESC

For example, if you want to sort by last name in ascending alphabetical order, you can use the following statement:

SELECT * FROM customers ORDER BY last_name ASC;

4. LIMIT

The LIMIT statement is used to limit the number of query results.

Syntax: SELECT column_name(s) FROM table_name LIMIT number

For example, if you only want to retrieve the first 10 results in the customers table, you can use the following statement:

SELECT * FROM customers LIMIT 10;

5. LIKE

The LIKE statement is used to search for pattern matching strings in the query.

Syntax: SELECT column_name(s) FROM table_name WHERE column_name LIKE pattern

For example, if you want to select the information of people whose last name starts with "S" from the customers table, you can use the following Statement:

SELECT * FROM customers WHERE last_name LIKE "S%";

6. GROUP BY

GROUP BY statement is used to group query results, usually with aggregation functions are used together.

Syntax: SELECT column_name, aggregate_function(column_name) FROM table_name GROUP BY column_name

For example, if you want to select the number of orders for each customer from the table, you can use the following statement:

SELECT customer_name, COUNT(*) FROM orders GROUP BY customer_name;

This will return the following results:

##John5Lisa 8Sarah3

customer_name	COUNT(*)

The above are common MySQL query table statements, these statements can satisfy most Partial query requirements. Of course, you can also mix and match these statements to meet more complex query needs.

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