select into statement usage

The SELECT INTO statement inserts data from one table to another table. The syntax is: SELECT INTO target table [field list] FROM source table [WHERE condition]. Can be used to create new tables, move or update data.

SELECT INTO statement usage

The SELECT INTO statement allows you to select data from one table and insert it into another in a table. The syntax is:

<code>SELECT INTO 目标表 [字段列表]
FROM 源表
[WHERE 条件]</code>

Syntax description:

• Target table: The name of the table into which data is to be inserted.
• Field list: Optional, the fields to be selected from the source table. If not specified, all fields are selected.
• Source table: The name of the table containing the data to be selected.
• WHERE condition: Optional, used to filter rows in the source table.

Usage:

The SELECT INTO statement is used for the following purposes:

• Create a copy or subset of a new table.
• Move data from one table to another.
• Update or supplement data into an existing table.

Example:

Copy a table:

<code>SELECT INTO 新表 * FROM 旧表;</code>

Insert certain fields into the new table :

<code>SELECT INTO 新表 (字段1, 字段2) FROM 旧表;</code>

Update existing table:

<code>SELECT INTO 表名 (字段1, 字段2)
FROM 另一个表
WHERE 表名.主键 = 另一个表.主键;</code>

Note:

• In the target table The field structure must be compatible with the field structure in the source table.
• If the target table does not exist, it will be created automatically.
• If some fields in the target table do not exist in the source table, these fields will be filled with NULL.
• If some fields in the source table do not exist in the target table, these fields will be ignored.

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