Assuming that I have a query as the following
update Object set status=#{statusValue} where attr1=#{par1} or attr2=#{par2};
I would like to know the processing order of the condition in the WHERE clause. I mean, if attr1=#{par1} result TRUE, the value of par2 is checked or is sufficient the first condition?
Thx
MySQL evaluates boolean expressions left to right, and supports short-circuiting like most programming languages do.
In an expression x AND y, if x is false, then y is not evaluated.
In an expression x OR y, if x is true, then y is not evaluated.
You can test this:
SET @y := 0;
SELECT true OR (@y := 42);
SELECT @y;
Should yield 0, because the right side of the expression was not evaluated.
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