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