Which is faster/best? SELECT * or SELECT column1, colum2, column3, etc

后端 未结 30 3076
清歌不尽
清歌不尽 2020-11-21 23:59

I\'ve heard that SELECT * is generally bad practice to use when writing SQL commands because it is more efficient to SELECT columns you specificall

30条回答
  •  难免孤独
    2020-11-22 00:39

    As with most problems, it depends on what you want to achieve. If you want to create a db grid that will allow all columns in any table, then "Select *" is the answer. However, if you will only need certain columns and adding or deleting columns from the query is done infrequently, then specify them individually.

    It also depends on the amount of data you want to transfer from the server. If one of the columns is a defined as memo, graphic, blob, etc. and you don't need that column, you'd better not use "Select *" or you'll get a whole bunch of data you don't want and your performance could suffer.

提交回复
热议问题