• 表达式语法(Expression Syntax)

    表达式语法(Expression Syntax)

    在 TiDB 中，以下规则是表达式的语法，你可以在 parser/parser.y 中找到定义。TiDB 的语法解析是基于 yacc 的。

    1. Expression:
    2.       singleAtIdentifier assignmentEq Expression 
    3.     | Expression logOr Expression
    4.     | Expression "XOR" Expression
    5.     | Expression logAnd Expression 
    6.     | "NOT" Expression
    7.     | Factor IsOrNotOp trueKwd
    8.     | Factor IsOrNotOp falseKwd
    9.     | Factor IsOrNotOp "UNKNOWN"
    10.     | Factor
    12. Factor:
    13.       Factor IsOrNotOp "NULL"
    14.     | Factor CompareOp PredicateExpr 
    15.     | Factor CompareOp singleAtIdentifier assignmentEq PredicateExpr 
    16.     | Factor CompareOp AnyOrAll SubSelect 
    17.     | PredicateExpr
    19. PredicateExpr:
    20.       PrimaryFactor InOrNotOp '(' ExpressionList ')'
    21.     | PrimaryFactor InOrNotOp SubSelect 
    22.     | PrimaryFactor BetweenOrNotOp PrimaryFactor "AND" PredicateExpr 
    23.     | PrimaryFactor LikeOrNotOp PrimaryExpression LikeEscapeOpt 
    24.     | PrimaryFactor RegexpOrNotOp PrimaryExpression 
    25.     | PrimaryFactor
    27. PrimaryFactor:
    28.       PrimaryFactor '|' PrimaryFactor
    29.     | PrimaryFactor '&' PrimaryFactor 
    30.     | PrimaryFactor "<<" PrimaryFactor 
    31.     | PrimaryFactor ">>" PrimaryFactor 
    32.     | PrimaryFactor '+' PrimaryFactor 
    33.     | PrimaryFactor '-' PrimaryFactor 
    34.     | PrimaryFactor '*' PrimaryFactor 
    35.     | PrimaryFactor '/' PrimaryFactor 
    36.     | PrimaryFactor '%' PrimaryFactor 
    37.     | PrimaryFactor "DIV" PrimaryFactor 
    38.     | PrimaryFactor "MOD" PrimaryFactor 
    39.     | PrimaryFactor '^' PrimaryFactor
    40.     | PrimaryExpression
    42. PrimaryExpression:
    43.       Operand
    44.     | FunctionCallKeyword
    45.     | FunctionCallNonKeyword
    46.     | FunctionCallAgg
    47.     | FunctionCallGeneric
    48.     | Identifier jss stringLit
    49.     | Identifier juss stringLit
    50.     | SubSelect
    51.     | '!' PrimaryExpression 
    52.     | '~'  PrimaryExpression 
    53.     | '-' PrimaryExpression 
    54.     | '+' PrimaryExpression 
    55.     | "BINARY" PrimaryExpression 
    56.     | PrimaryExpression "COLLATE" StringName