| 功能 | Oracle 寫法 | DB2 寫法 |
|---|
| 取前 N 筆 | SELECT * FROM T WHERE ROWNUM <= N | SELECT * FROM T FETCH FIRST N ROWS ONLY 或 ROW_NUMBER() OVER() |
| 當前日期時間 | SELECT SYSDATE FROM DUAL | SELECT CURRENT TIMESTAMP FROM SYSIBM.SYSDUMMY1 |
| 字串連接 | A || B / CONCAT(A,B) | A || B / A CONCAT B |
| 查表結構 | DESC T / `USER_TAB_COLUMNS` | DESCRIBE TABLE T / `SYSCAT.COLUMNS` |
| 內連接 | FROM A,B WHERE A.ID=B.ID | FROM A INNER JOIN B ON A.ID=B.ID |
| 左外連接 | A.ID = B.ID (+) | FROM A LEFT OUTER JOIN B ON A.ID=B.ID |
| 右外連接 | A.ID (+) = B.ID | FROM A RIGHT OUTER JOIN B ON A.ID=B.ID |
| 全外連接 | FULL OUTER JOIN (10g+) | FROM A FULL OUTER JOIN B ON A.ID=B.ID |
