The UNION ALL and CASE operators are collation insensitive, and all string operands and the final results are assigned the collation label of the operand with the highest precedence.

• UNION ALL和CASE运算符不区分排序规则,所有的字符串操作数和最终结果都被赋以具有最高优先顺序的操作数的排序规则标签。