Oracle multi-row merge skills

The oracle multi-row merge technique often combines fields in a column when writing SQL statements. For example, the monthly salary of a person is listed, but each person can only take one row. In such scenarios, you may also use row-column conversion. However, if the information for this month is not fixed, you cannot use column-column conversion. After oracle10g, a function WMSYS. WM_CONCAT is provided, which can be easily implemented.

[SQL] select t. rank, WMSYS. WM_CONCAT (t. Name) TIME From t_menu_item t GROUP BY t. rank;

 

In this way, it is much more comfortable to look. Before this method is available, you may need to write a function by yourself, which is a little more troublesome.