You can also use row and column aliases with a SET clause, as mentioned previously. The row alias must not be the same as the name of the table. Column aliases must be unique with regard to the row alias to which they apply that is, no column aliases referring to columns of the same row may be the same. References to columns from queries on a single table, which may be a derived table.
One side effect is that you must qualify references to nonunique column names. To work around this restriction, rewrite the UNION as a derived table so that its rows can be treated as a single-table result set. Verbal Ability. Interview Questions. Company Questions. Artificial Intelligence. Cloud Computing. Data Science. Angular 7. Machine Learning. Data Structures. Operating System. Computer Network. Compiler Design. Computer Organization.
Beginning with MySQL 8. Using the row alias new , the statement shown previously using VALUES to access the new column values can be written in the form shown here:. If, in addition, you use the column aliases m , n , and p , you can omit the row alias in the assignment clause and write the same statement like this:. When using column aliases in this fashion, you must still use a row alias following the VALUES clause, even if you do not make direct use of it in the assignment clause.
You can also use row and column aliases with a SET clause, as mentioned previously. The row alias must not be the same as the name of the table.
0コメント