jet/internal/jet/operators.go
2022-01-10 16:43:17 +01:00

180 lines
4.7 KiB
Go

package jet
// Operators
const (
StringConcatOperator = "||"
StringRegexpLikeOperator = "REGEXP"
StringNotRegexpLikeOperator = "NOT REGEXP"
)
//----------- Logical operators ---------------//
// NOT returns negation of bool expression result
func NOT(exp BoolExpression) BoolExpression {
return newPrefixBoolOperatorExpression(exp, "NOT")
}
// BIT_NOT inverts every bit in integer expression result
func BIT_NOT(expr IntegerExpression) IntegerExpression {
if literalExp, ok := expr.(LiteralExpression); ok {
literalExp.SetConstant(true)
}
return newPrefixIntegerOperatorExpression(expr, "~")
}
//----------- Comparison operators ---------------//
// EXISTS checks for existence of the rows in subQuery
func EXISTS(subQuery Expression) BoolExpression {
return newPrefixBoolOperatorExpression(subQuery, "EXISTS")
}
// Eq returns a representation of "a=b"
func Eq(lhs, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, "=")
}
// NotEq returns a representation of "a!=b"
func NotEq(lhs, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, "!=")
}
// IsDistinctFrom returns a representation of "a IS DISTINCT FROM b"
func IsDistinctFrom(lhs, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, "IS DISTINCT FROM")
}
// IsNotDistinctFrom returns a representation of "a IS NOT DISTINCT FROM b"
func IsNotDistinctFrom(lhs, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, "IS NOT DISTINCT FROM")
}
// Lt returns a representation of "a<b"
func Lt(lhs Expression, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, "<")
}
// LtEq returns a representation of "a<=b"
func LtEq(lhs, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, "<=")
}
// Gt returns a representation of "a>b"
func Gt(lhs, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, ">")
}
// GtEq returns a representation of "a>=b"
func GtEq(lhs, rhs Expression) BoolExpression {
return newBinaryBoolOperatorExpression(lhs, rhs, ">=")
}
// Add notEq returns a representation of "a + b"
func Add(lhs, rhs Serializer) Expression {
return NewBinaryOperatorExpression(lhs, rhs, "+")
}
// Sub notEq returns a representation of "a - b"
func Sub(lhs, rhs Serializer) Expression {
return NewBinaryOperatorExpression(lhs, rhs, "-")
}
// Mul returns a representation of "a * b"
func Mul(lhs, rhs Serializer) Expression {
return NewBinaryOperatorExpression(lhs, rhs, "*")
}
// Div returns a representation of "a / b"
func Div(lhs, rhs Serializer) Expression {
return NewBinaryOperatorExpression(lhs, rhs, "/")
}
// Mod returns a representation of "a % b"
func Mod(lhs, rhs Serializer) Expression {
return NewBinaryOperatorExpression(lhs, rhs, "%")
}
// --------------- CASE operator -------------------//
// CaseOperator is interface for SQL case operator
type CaseOperator interface {
Expression
WHEN(condition Expression) CaseOperator
THEN(then Expression) CaseOperator
ELSE(els Expression) CaseOperator
}
type caseOperatorImpl struct {
ExpressionInterfaceImpl
expression Expression
when []Expression
then []Expression
els Expression
}
// CASE create CASE operator with optional list of expressions
func CASE(expression ...Expression) CaseOperator {
caseExp := &caseOperatorImpl{}
if len(expression) > 0 {
caseExp.expression = expression[0]
}
caseExp.ExpressionInterfaceImpl.Parent = caseExp
return caseExp
}
func (c *caseOperatorImpl) WHEN(when Expression) CaseOperator {
c.when = append(c.when, when)
return c
}
func (c *caseOperatorImpl) THEN(then Expression) CaseOperator {
c.then = append(c.then, then)
return c
}
func (c *caseOperatorImpl) ELSE(els Expression) CaseOperator {
c.els = els
return c
}
func (c *caseOperatorImpl) serialize(statement StatementType, out *SQLBuilder, options ...SerializeOption) {
out.WriteString("(CASE")
if c.expression != nil {
c.expression.serialize(statement, out, FallTrough(options)...)
}
if len(c.when) == 0 || len(c.then) == 0 {
panic("jet: invalid case Statement. There should be at least one WHEN/THEN pair. ")
}
if len(c.when) != len(c.then) {
panic("jet: WHEN and THEN expression count mismatch. ")
}
for i, when := range c.when {
out.WriteString("WHEN")
when.serialize(statement, out, NoWrap)
out.WriteString("THEN")
c.then[i].serialize(statement, out, NoWrap)
}
if c.els != nil {
out.WriteString("ELSE")
c.els.serialize(statement, out, NoWrap)
}
out.WriteString("END)")
}
// DISTINCT operator can be used to return distinct values of expr
func DISTINCT(expr Expression) Expression {
return newPrefixOperatorExpression(expr, "DISTINCT")
}