摘要:
Operator Description= Equal or != Not equalGreater than=Greater than or equalANYCompares one value with any value in a listALL Compares one value with... 阅读全文
摘要:
1. dual is a table that contains a single row.2. The dual table has one VARCHAR2 column named dummy.3. dual contains a single row with the value X.des... 阅读全文