This module includes the standard mathematical methods (+, -, *, and /) that are defined on objects that can be used in a numeric context in SQL (Symbol, LiteralString, and +SQL::GenericExpression+).
:a + :b # "a" + "b" :a - :b # "a" - "b" :a * :b # "a" * "b" :a / :b # "a" / "b"
One exception to this is if + is called with a String or StringExpression, in which case the || operator is used instead of the + operator:
:a + 'b' # "a" || 'b'
Use || as the operator when called with StringExpression and String instances, and the + operator for LiteralStrings and all other types.
# File lib/sequel/sql.rb, line 770 def +(ce) case ce when LiteralString NumericExpression.new(:+, self, ce) when StringExpression, String StringExpression.new(:'||', self, ce) else NumericExpression.new(:+, self, ce) end end
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