142 lines
3.3 KiB
Go
142 lines
3.3 KiB
Go
package jet
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const (
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StringConcatOperator = "||"
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)
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//----------- Logical operators ---------------//
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// NOT returns negation of bool expression result
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func NOT(exp BoolExpression) BoolExpression {
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return newPrefixBoolOperator(exp, "NOT")
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}
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// BIT_NOT inverts every bit in integer expression result
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func BIT_NOT(expr IntegerExpression) IntegerExpression {
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return newPrefixIntegerOperator(expr, "~")
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}
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//----------- Comparison operators ---------------//
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// EXISTS checks for existence of the rows in subQuery
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func EXISTS(subQuery Expression) BoolExpression {
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return newPrefixBoolOperator(subQuery, "EXISTS")
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}
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// Returns a representation of "a=b"
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func eq(lhs, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, "=")
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}
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// Returns a representation of "a!=b"
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func notEq(lhs, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, "!=")
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}
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func isDistinctFrom(lhs, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, "IS DISTINCT FROM")
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}
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func isNotDistinctFrom(lhs, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, "IS NOT DISTINCT FROM")
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}
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// Returns a representation of "a<b"
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func lt(lhs Expression, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, "<")
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}
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// Returns a representation of "a<=b"
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func ltEq(lhs, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, "<=")
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}
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// Returns a representation of "a>b"
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func gt(lhs, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, ">")
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}
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// Returns a representation of "a>=b"
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func gtEq(lhs, rhs Expression) BoolExpression {
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return newBinaryBoolOperator(lhs, rhs, ">=")
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}
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// --------------- CASE operator -------------------//
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// CaseOperator is interface for SQL case operator
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type CaseOperator interface {
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Expression
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WHEN(condition Expression) CaseOperator
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THEN(then Expression) CaseOperator
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ELSE(els Expression) CaseOperator
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}
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type caseOperatorImpl struct {
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ExpressionInterfaceImpl
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expression Expression
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when []Expression
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then []Expression
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els Expression
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}
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// CASE create CASE operator with optional list of expressions
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func CASE(expression ...Expression) CaseOperator {
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caseExp := &caseOperatorImpl{}
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if len(expression) > 0 {
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caseExp.expression = expression[0]
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}
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caseExp.ExpressionInterfaceImpl.Parent = caseExp
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return caseExp
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}
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func (c *caseOperatorImpl) WHEN(when Expression) CaseOperator {
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c.when = append(c.when, when)
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return c
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}
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func (c *caseOperatorImpl) THEN(then Expression) CaseOperator {
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c.then = append(c.then, then)
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return c
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}
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func (c *caseOperatorImpl) ELSE(els Expression) CaseOperator {
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c.els = els
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return c
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}
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func (c *caseOperatorImpl) serialize(statement StatementType, out *SqlBuilder, options ...SerializeOption) {
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out.WriteString("(CASE")
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if c.expression != nil {
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c.expression.serialize(statement, out)
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}
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if len(c.when) == 0 || len(c.then) == 0 {
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panic("jet: invalid case Statement. There should be at least one WHEN/THEN pair. ")
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}
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if len(c.when) != len(c.then) {
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panic("jet: WHEN and THEN expression count mismatch. ")
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}
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for i, when := range c.when {
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out.WriteString("WHEN")
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when.serialize(statement, out, noWrap)
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out.WriteString("THEN")
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c.then[i].serialize(statement, out, noWrap)
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}
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if c.els != nil {
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out.WriteString("ELSE")
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c.els.serialize(statement, out, noWrap)
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}
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out.WriteString("END)")
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}
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