dolphin-操作符优先级

操作符从高到低排序如下（同一行的操作符拥有相同的优先级）：

COLLATE
OR_OR_SYM
^
*, /, %
+, -
IS
ISNULL
NOTNULL
Op, OPERATOR '@'
REGEXP, RLIKE
DIV, MOD
IN_P, NOT_IN
BETWEEN, NOT_BETWEEN
LIKE, NOT_LIKE
BINARY
'=', '<', '>', CmpOp ('!=', '<>', '<=', '>=', '^=')
CmpNullOp ('<=>'), COLON_EQUALS (':=')
NOT
AND
XOR
OR

• 当dolphin.b_compatibility_mode为TRUE时，PIPES_AS_CONCAT默认将开启,||则为OR_OR_SYM，作为字符串连接；当PIPES_AS_CONCAT关闭时，||则为逻辑OR操作符。