how to select multiple rows using where (two conditions) in sql?

Question

When the condition is based on one column, I can use either IN, AND, or OR, but if the condition is based on two columns, how to write the query? For example, I need to set up the value of column 1 to NULL in the following rows: column 2 = 'red' AND column 3 =' Monday', column 2 = 'yellow' and column 3 = 'Tuesday'. 'red' or 'yellow' is not unique in column 2, the same for 'Monday' and 'Tuesday'. I have quite of few of rows need to be updated. How can I do this in one query?

column1   column2    column3    
1         red        Monday    
2         red        Tuesday    
3         yellow     Monday    
4         yellow     Tuesday    
5         green      Wednesday

The results look like this:

column1   column2    column3    
NULL      red        Monday    
2         red        Tuesday    
3         yellow     Monday    
NULL      yellow     Tuesday    
5         green      Wednesday

Marc B · Accepted Answer · 2016-10-03 22:02:13Z

2

WHERE clauses boil down to a simple true/false value: true - the row matches, so do something. false - no match, don't do anything.

If you have multiple independent conditions, then

WHERE (condition1) OR (condition2) OR ...

And each of those sub-conditions can be as arbitrarily complicated/simple as you need, including having their own in clauses:

WHERE (foo IN ('a','b','c')) OR (bar IN ('p','q', 'r')) OR (baz = 42)

answered Oct 3, 2016 at 22:02

Marc B

362k44 gold badges433 silver badges508 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Marek Janoud · Accepted Answer · 2016-10-03 22:02:45Z

1

UPDATE yourTable SET column1 = NULL WHERE (column2 = 'red' AND column3 = 'Monday') OR (column2 = 'yellow' AND column3 = 'Tuesday')

answered Oct 3, 2016 at 22:02

Marek Janoud

4303 silver badges8 bronze badges

Collectives™ on Stack Overflow

how to select multiple rows using where (two conditions) in sql?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related