Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
355 views
in Technique[技术] by (71.8m points)

sql server - Does the order of columns in a WHERE clause matter?

Does the order of the columns in a WHERE clause effect performance?

e.g.

Say I put a column that has a higher potential for uniqueness first or visa versa?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

With a decent query optimiser: it shouldn't.

But in practice, I suspect it might.

You can only tell for your cases by measuring. And the measurements will likely change as the distribution of data changes in the database.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...