警告是什麼意思?Toad for Oracle格式化程序的建議
爲什麼第二個例子比第一個更糟?
SELECT product_id, prod.name name, sample_id
FROM lims.sample JOIN lims.product prod USING (product_id)
與
SELECT product_id, prod.name name, sample_id
FROM (SELECT sample_id, product_id FROM lims.sample)
JOIN lims.product prod
/* ADVICE: [131] This item has not been declared, or it refers to a label */
USING (product_id)
/* ADVICE:
ADVICE SUMMARY
Count Recommendation
----- --------------
1 [131] This item has not been declared, or it refers to a label
The Oracle equivalent error messages are PLS-00320 and
PLS-0321.
*/
FYI:這兩個查詢運行正常,並返回相同的結果。
任何猜測都是可以的。 – Steven 2009-06-04 22:59:00