Method getFunction

pkg/expression/builtin_cast.go:623–645

(ctx BuildContext, args []Expression)

}

func (c *castAsArrayFunctionClass) getFunction(ctx BuildContext, args []Expression) (sig builtinFunc, err error) {
	if err := c.verifyArgs(ctx.GetEvalCtx(), args); err != nil {
		return nil, err
	}
	arrayType := c.tp.ArrayType()
	switch arrayType.GetType() {
	case mysql.TypeYear, mysql.TypeJSON, mysql.TypeFloat, mysql.TypeNewDecimal:
		return nil, ErrNotSupportedYet.GenWithStackByArgs(fmt.Sprintf("CAST-ing data to array of %s", arrayType.String()))
	}
	if arrayType.EvalType() == types.ETString && arrayType.GetCharset() != charset.CharsetUTF8MB4 && arrayType.GetCharset() != charset.CharsetBin {
		return nil, ErrNotSupportedYet.GenWithStackByArgs("specifying charset for multi-valued index")
	}
	if arrayType.EvalType() == types.ETString && arrayType.GetFlen() == types.UnspecifiedLength {
		return nil, ErrNotSupportedYet.GenWithStackByArgs("CAST-ing data to array of char/binary BLOBs with unspecified length")
	}

	bf, err := newBaseBuiltinFunc(ctx, c.funcName, args, c.tp)
	if err != nil {
		return nil, err
	}
	sig = &castJSONAsArrayFunctionSig{bf}
	return sig, nil
}

type castJSONAsArrayFunctionSig struct {
	baseBuiltinFunc