Shulou(Shulou.com)05/31 Report--

This article introduces to you how to achieve sub-query in mysql, the content is very detailed, interested friends can use for reference, I hope it can be helpful to you.

Subqueries can be divided into from where and subqueries.

Classification table:

[sql]

Mysql > select * from category

+-+ +

| | id | c_name |

+-+ +

| | 1 | ios |

| | 2 | android |

| | 3 | sb |

+-+ +

3 rows in set

Commodity list:

[sql]

Mysql > select * from goods

+-- +

| | id | name | cat_id | price | num | |

+-- +

| | 1 | Apple | 1 | 4999 | 2 |

| | 2 | nexus4 | 2 | 1999 | 3 |

| | 4 | Honor 2 | 2 | 1888 | 5 |

| | 6 | Samsung | 2 | 3000 | 2 |

+-- +

6 rows in se

Requirements: only find out the classification of goods under the classification

[sql]

Mysql > select * from category c where exists (select * from goods where cat_id=c.id)

+-+ +

| | id | c_name |

+-+ +

| | 1 | ios |

| | 2 | android |

+-+ +

2 rows in set

This is the end of how to realize the subquery in mysql. I hope the above content can be helpful to you and learn more knowledge. If you think the article is good, you can share it for more people to see.

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