Oracle使用須要注意的一些技巧

使用or時，Oracle會將or左右的語句視爲兩個分別查詢，以下方語句

select * from T_JC_tools where jc_id='11024418' and eff_Station is null or eff_station='北京' and  jc_id='11024418' and delete_time is null;

實際中會將前面和後面總體分割開

select * from T_JC_tools where （jc_id='11024418' and eff_Station is null ）or （eff_station='北京' and  jc_id='11024418' and delete_time is null）;

因此咱們須要在or查詢的條件先後加上（）保證查詢的準確性

select * from T_JC_tools where jc_id='11024418' and (eff_Station is null or eff_station='北京') and  jc_id='11024418' and delete_time is null;