環境： Win2000 SP4 BCB6 Update4 Zeos 6.5.1 問題： mysql> show columns from tb_dsales_record; --------- -------------------------- ------ ----- ---------- ------- | Field | Type | Null | Key | Default | Extra | --------- -------------------------- ------ ----- ---------- ------- | no | int(8) unsigned zerofill | YES | | 00000000 | | | product | varchar(20) | YES | | NULL | | | qty | int(11) | YES | | 1 | | | uprice | float(4,2) | YES | | 0.00 | | | amount | float(4,2) | YES | | 0.00 | | | joined | int(11) | YES | | 1 | | | odate | date | YES | | NULL | | --------- -------------------------- ------ ----- ---------- ------- 7 rows in set (0.00 sec) mysql> select * from tb_dsales_record; ---------- --------- ------ -------- -------- -------- ------------ | no | product | qty | uprice | amount | joined | odate | ---------- --------- ------ -------- -------- -------- ------------ | 00000003 | 10KG | 3 | 0.80 | 2.40 | 1 | 2005-06-02 | | 00000003 | 10KG | 3 | 0.80 | 1.20 | 2 | 2005-06-02 | | 00000003 | 10KG | 3 | 0.80 | 2.40 | 1 | 2005-06-02 | | 00000003 | 10KG | 32 | 0.80 | 25.60 | 1 | 2005-06-02 | | 00000003 | 10KG | 3 | 0.80 | 1.20 | 2 | 2005-06-02 | ---------- --------- ------ -------- -------- -------- ------------ 5 rows in set (0.01 sec) mysql> select * from tb_dsales_record where uprice=0.80; Empty set (0.00 sec) mysql> select * from tb_dsales_record where uprice='0.80'; Empty set (0.00 sec) 請問要怎樣才可以查詢出uprice=0.80的資料？

irvinehing 您好：    這是 MySQL 的 Bug，在 MySQL 的文件中有這麼一段說明： If you are comparing FLOAT or DOUBLE columns with numbers that have decimals, you can't use equality (=) comparisons. This problem is common in most computer languages because not all floating-point values can be stored with exact precision. In some cases, changing the FLOAT to a DOUBLE fixes this. See Section A.5.8, “Problems with Floating-Point Comparisons”. 由這一段說明可以知道 float 型態的資料不可以用 = 來比對，在某些狀況下，改用 double 型態可以獲得解決，您可以先試試看，若仍不行的話，就查看一下 Help 中的 A.5.8. Problems with Floating-Point Comparisons 那一段的說明吧。