AS for Column¶
Function¶
This statement is used to specify an alias for a column.
Syntax¶
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.
SELECT n FROM (SELECT name AS n FROM simple_table WHERE score > 90) m WHERE n = "xiaoming";