Database MySQL simple operation (iii)

1.3 Multi-Table query

1.3.1 Connection query:

#内连接:

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Self-connect query:

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# External Connection

Left OUTER JOIN (can query all records of table name 1, and table name 2 can only find matching records)

List of SELECT property Names from table name 1 left JOIN table name 2 on table name 1. property name 1= table Name 2. property Name 2;

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# RIGHT OUTER join (can query all records of table name 2, and table name 1 can only find matching records):

First, insert some values into the right table:

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Then make the right outer join query:

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1.4 Modifying fields for some records

The previous simple introduction (insert INTO) and check (select * from), here goes on to say change.

1.4.1 Single-table update

The simplest expression is:

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Add some more restrictions, as follows:

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The results are as follows:

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1.4.2 Multi-table update

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Well, this example doesn't work at all, because we're only associated with SIDS, which can be written separately for two updates.

However, in the case of multiple table updates, if it is related to two tables, such as having a turn-out table and a transfer table have interdependent keys, so that some States are closely related to update together. (It seems to be a good business.)

......

The above results are as follows:

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1.5 Delete

For a detailed MySQL delete operation, you can view the article

Http://www.cnblogs.com/ggjucheng/archive/2012/11/06/2756420.html

Single-table record deletion:

DELETE from table name WHERE conditional expression [ORDER by field][limit record rows]

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The original data is this:

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Database MySQL simple operation (iii)