AS for Column

Function

This statement is used to specify an alias for a column.

Syntax

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SELECT attr_expr [AS] alias, attr_expr [AS] alias, ... FROM table_reference;

Keyword

• alias: gives an alias for the attr_expr field.
• AS: Whether to add AS does not affect the result.

Precautions

• The to-be-queried table must exist. Otherwise, an error is reported.
• The alias must be specified before execution of the statement. Otherwise, an error is reported. You are advised to specify a unique alias.

Example

Run SELECT name AS n FROM simple_table WHERE score > 90 to obtain the subquery result. The alias n for name can be used by external SELECT statement.

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SELECT n FROM (SELECT name AS n FROM simple_table WHERE score > 90) m WHERE n = "xiaoming";